The Years & Years singer, 32, appeared at the weekend festival in London’s Brockwell Park, which put on over 200 pop acts for 60,000 fans.
Attendees have already been treated to the likes of Kelis, Kelly Rowland and even Gemma Collins (as well as a slightly unexpected Bill Murray).
On Sunday though, Olly presented quite the finale when he was joined onstage by half of Girls Aloud in the form(s) of Nicola Roberts and Kimberley Walsh.
Even better, the two pop icons then joined him in a performance of their smash-hit single The Promise.
Videos spread like wildfire on social media of their rendition, with actor and artist Olly showing he was very much down with the choreography and trademark poses of the band as the trio stood at their microphones.
With Olly stood in the middle wearing a black vest and black leather-look trousers with what appeared to be gold sparkly shorts over the top, while Kimberley and Nicola flanked him either side.
Both ladies looked delightfully glam, with Kimberley, 41, in an off-the-shoulder black gown with silver diamante detailing.
Meanwhile, Nicola, 37, opted for a white feather-trim dress with contrasting black full-length gloves.
Fans were living for it online, with one admitting: ‘The FOMO I have right now.’
‘I’m dying. Knew I should’ve been there,’ added another.
Others also loved how the crowd joined in to sing along with late member Sarah Harding’s famous line in the song.
‘The crowd singing Sarah’s “walking primrose” line,’ praised one social media user, with a row of emoji signalling their appreciation of the move.
The band – which consisted of Harding, Kimberley, Nicola, Cheryl and Nadine Coyle – hosted a charity ball last year to raise money for Cancer Research in honour of Harding, named after the lyric too.
Girls Aloud have avoided committing to reuniting to perform together any time soon after Harding’s death, but fans were slightly confused that Nadine had performed solo at Mighty Hoopla the day before.
She had wowed crowds with her set and a vibrant green mini-dress on Saturday, but there was no sign of either Kimberley or Nicola then.
‘It’s so weird that Nicola, Kimberley & Nadine all performed Girls Aloud songs at Hoopla this weekend but won’t reunite,’ mused one fan.
However, Kimberley recently insisted the band all share a close friendship, which has deepened since Harding’s tragic death.
‘It is a long friendship. It’s really nice. I feel close to all of the girls – it’s genuinely a close friendship where we text daily. We are in each other’s lives, we know what’s going on,’ said the 41-year-old.
She added to the Sun on Sunday’s Fabulous magazine in April: ‘Obviously with everything that’s happened, we’re really as tight as we’ve ever been at the moment. You just have to lean on each other, don’t you?’
Got a story?
If you’ve got a celebrity story, video or pictures get in touch with the Metro.co.uk entertainment team by emailing us [email protected], calling 020 3615 2145 or by visiting our Submit Stuff page – we’d love to hear from you.
MORE : Dannii Minogue returning as the ultimate gay matchmaker for I Kissed A Girl after I Kissed A Boy success
MORE : Britain’s Got Talent 2023 winner announced as Viggo Venn crowned after close and eventful final
For all the latest Entertainment News Click Here
For the latest news and updates, follow us on Google News.
