She announced her plans to marry Joshua Sasse in February and it seems Kylie Minogue wants to get some wedding practice in ahead of the big day.

The Australian singer opted for a white, bridal-esque Dolce and Gabbana gown – that could have taken her straight up the aisle – to serenade the Queen in yet another celebration to mark her 90th birthday on Sunday at Windsor Castle.

The pint-sized star sang a specially arranged version of I Believe In You alongside an orchestra at the star-studded bash that also included members of the royal family, who sat alongside the birthday gal in the royal box.

While her performance went down a treat, the former Neighbours star was somewhat upstaged by an chubby, white Shetland pony.

As Minogue (sans Charlene-esque perm) belted out her 2007 hit, French horse whisperer Jean-Francois Pignon had 10 bareback horses and ponies perform a routine, and Twitter was enthralled by the little pony that lay on its back and kicked its legs in the air.

"Kylie definitely just got upstaged by a chunky little white pony. Adoorrrrable!! #Queens90thBirthday," one wrote.

While another added: "That awkward moment when Kylie Minogue gets upstaged by a Shetland pony #Queens90thBirthday."

More than 900 horses took part in the event, while other performers included tenor Andrea Bocelli, opera singer Katherine Jenkins, singer-songwriter Jess Glynne, soul singer Beverley Knight, James Blunt and Dame Shirley Bassey.

Presenters Ant and Dec took charge on the night for the two-hour TV special that also included John Boyega, Martin Clunes, Damian Lewis, Imelda Staunton and comic Jennifer Saunders.

Fittingly, The Queen star Helen Mirren took the audience through the Queen's teenage years.

Sunday's concert is the highlight of a four-day pageant at Windsor. Further events will take place around her official birthday on June 11, including a street party for 10,000 guests close to Buckingham Palace.