It could just be that those who manage to succeed in the tough world of movies have the sort of drive that also enables them to thrive in business. But well-known, well-paid Hollywood stars are also often in a strong position to start anew and try their hand at something fresh.

Either way, forget thespsing, these days it's apparently all about investing.

Here's a selection of movie stars with surprisingly successful sidelines:

Jared Leto

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Leto in his latest role as the Joker in Suicide Squad.

When he isn't winning Oscars, or being a wildly successful rock musician, or playing one of the most iconic super-villains of all time, or complaining about how his role as one of the greatest super-villains of all time has been edited down, Jared Leto is a pretty savvy investor.

Almost a decade ago, he astutely decided that the future lay in tech and poured money into businesses such as Uber, Reddit and Airbnb (all now household names).

The 44-year-old, who is reported to have a net worth of about $US40 million, also started his own digital marketing and social media business, The Hive, in 2012. This was swiftly followed by a VIP backstage experiences company, The One and Only Golden Tickets, and Vyrt, which sells online digital streaming "tickets" to live concerts for those unable to attend in person.

His success, he says, sprang from skills he picked up during his early days with band 30 Seconds to Mars, when he was forced through necessity to look after the business, managerial and marketing side of things.

"It put me on the path early on to be independent and entrepreneurial. And it lead me to the tech world," he said in a 2016 interview.

"In a band...it's very similar to a start-up. You're a few people in a garage...It put me on the path early on to be independent and entrepreneurial. And it lead me to the tech world."

Jessica Alba

Jessica Alba has created a retail empire around hypoallergenic baby products. Photo: Getty

Jessica Alba is perhaps best known for her breakthrough role in TV series Dark Angel, her turn as Nancy Callahan in the Sin City movies, and her role in the Fantastic Four movies (the silly, fun Tim Story ones, rather than the 2015 Josh Trank gloomflop). But in recent years, the actress has been at the helm of successful billion dollar business The Honest Company.

The company, whose motto is "Honestly safe, effective essentials for family and home", was conceived after Alba was distressed to find that her newborn daughter had broken out in hives after suffering an allergic reaction to a detergent. She became convinced that there was a market for 100 per cent naturally sourced, hypoallergenic baby products and finally managed to convince investors to come on board and help her launch in 2012.

Four years later, The Honest Company is valued at $US1.7 billion, and Alba, who has an estimated net worth of $US200 million, has been labelled "America's richest self-made woman" (by Forbes Magazine).

Ashton Kutcher

Ashton Kutcher has made a series of savvy investments. Photo: Getty Images

Like Jared Leto, Kutcher is a smart investor, with an eye for promising technology-based start-ups and a keen sense for ideas and products that might take off. (The film might have been slated, but it's easy to understand why director Joshua Michael Stern might have seen Kutcher as a convincing choice for entrepreneur Steve Jobs in his 2013 biopic Jobs).

Through his own venture capital company A-Grade Investments, Kutcher has  invested in now-familiar names such as Spotify, Flipboard, Shazam, Airbnb and Uber.

He was also savvy enough to buy a share in Skype in 2009 – enabling him to reportedly triple his investment when the company was picked up by Microsoft in 2011.

"If we can create efficiencies in that which is mundane, then we accelerate our paths to happiness," he said in 2013, explaining how he chooses which businesses to invest in. "The companies that will ultimately do well are the companies that chase happiness. If you find a way to help people find love, or health or friendship, the dollar will chase that."

His current net worth is believed to be about $US160 million.

Kevin Costner

Kevin Costner has made a fortune from technology which cleans up oil spills. Photo: Getty Images

Want to liven up dull dinner parties with a moderately interesting fact about Waterworld star Kevin Costner? In the Nineties, the actor (who is now worth an estimated $US150 million) began investing in water and oil separating centrifuges, pouring millions of dollars into developing the technology (which is used to help clean up ocean oil spills).

His hard work paid off in 2010 after the Deepwater Horizon disaster: BP placed a $US52 million order with his company, including an upfront deposit of $18US million. His success was marred by controversy, however. Fellow actor Stephen Baldwin and his friend Spyridon Contogouris had both been shareholders in the company behind the centrifuges, Ocean Therapy Solutions – but opted to sell their shares ahead of the big BP order. They alleged in court that Costner had deliberately withheld crucial information from them, and that they never would have sold had they known about the forthcoming BP deal. The jury eventually ruled in Costner's favour.

In addition to this, there were damaging media reports about just how effective the centrifuges really were. A 2011 Guardian article, for instance, reports on allegations that Costner's oil-cleaning solution was prioritised over other, potentially more effective solutions.

Gwyneth Paltrow

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Gwyneth Paltrow's Goop website has 4 million viewers a month. Photo: Dimitrios Kambouris

OK, so her knack for dishing out patronising advice and penchant for "sex dust breakfasts" (a phrase so nauseating it makes us wish we hadn't just eaten own our breakfasts) are pretty easy to mock. But turns out we shouldn't have been so quick to laugh. Ever since 2008, when her lifestyle company Goop was founded, Paltrow has managed to capitalise on the trend for high-end (aka ridiculously expensive) health and beauty products, catering to our obsession with all things "natural" and simultaneous, arguably contradictory craving for luxury. Like her or loathe her, she's managed to carve out a pretty credible alternate career.

Despite reports of debts in 2014, Goop also appears to be growing steadily: the website (part blog, part online shop)  pulls in 4 million viewers a month, and more than 1 million people subscribe.

Paltrow's recent decision to distance herself from her own product also feels like a wise choice – indicating that she's interested in the long-term success of the business.

"In order to build the brand I want to build, its scalability is limited if I connect it to the brand," she said. "So I always think, 'How can I grow the brand? How can I separate myself from the brand? And I think its going to be more its own brand."

"My dream is that one day no one will remember that I had anything to do with it."

Jessica Simpson

Jessica Simpson's clothing line brings in $US1 billion annually. 

These days, it feels like almost every celebrity in existence has brought out their own personally-branded fashion line…but The Jessica Simpson Collection, named after its singer-actress founder,  has proved more lucrative than most.

Since its inception in 2006, at which point it focused just on shoes, the business has grown with Audrey II-like rapidity (although it thrives off happy consumers, rather than blood).

The reason Simpson has succeeded where so many others has failed can perhaps be put down to the fact that she's interested in making clothing and accessories that will appeal to ordinary customers, rather than just the Hollywood elite.

"I have been every size on the planet, and I understand – I feel like I understand women," she said in 2014. "I know there's all different kinds, you know. There's life and a whole entire world beyond LA and New York. And I do understand the Middle America, and their mindset."

According to Forbes, the clothing line now annually brings in about $US1 billion, while Simpson's own income from the business  is "10s of millions" of dollars a year. Her reported net worth is about $US150 million.

Drew Barrymore

Drew Barrymore has a lucrative cosmetics line. Photo: Getty Images

Drew Barrymore, who is reported to have a net worth of $US125 million, is known for being a successful actress and (through her company Flower Films) movie producer and it's true that the bulk of her earnings probably still come from the movie world.

In addition to her film career, however, the ET star is the owner of the Flower Beauty brand of cosmetics, launched in 2013 and sold across the US in Walmart supermarkets , and of spectacles line Flower Eyewear, also stocked in Walmart.

Because Barrymore promotes the brand herself, Flower Beauty is able to save money on advertising, focusing instead on spending more on ingredients, and offering a luxury product at a Walmart-friendly price.

She's currently planning to expand the business, taking on markets outside the US, in Europe, Australia and China.

Flower Beauty is growing by the day. We started in 1600 doors and now we're in almost 4000. We also just launched Flower Eyewear, and we're number one at Walmart, which I'm very proud to say because I'm relieved it worked. Reviews are important – social media and creating a good marketing campaign that really speaks to women," she said in January 2016.

Barrymore is also prepared to put in the time and hard work needed to expand her business overseas.

"Nothing happens overnight," she told Fashion Week Daily.  "Which is scary, because you want it to financially work overnight. But slow and steady wins the race. The companies that I aspire to be, like Honest and what Gwyneth Paltrow is doing with Goop, have taken years. You can see that it is their blood sweat and tears and it's isn't celebrity name slapping. More power to those people."

– The Telegraph, London