The Spice Girls had their own mini-reunion performance at Victoria Beckham's 50th bday bash Saturday night ... and hubby David made sure to capture it all on camera!

Every millennial's dream came true as Posh, Baby (Emma Bunton), Sporty (Melanie Chisholm), Ginger (Geri Halliwell) and Scary (Melanie Brown) Spice  performed an impromptu rendition of their hit song "Stop."

As fans know, the group last toured as a four-piece in 2019 without Victoria ... and the last time the entire group came together for a live performance was at the London Olympics closing ceremony in 2012.

As we previously reported, the UK event was star-studded ... with celebs like Tom Cruise, Gordon Ramsay, Guy Ritchie, Jason Statham, Victoria's Secret Angel Rosie Huntington-Whiteley, Marc Anthony and his new wife Nadia Ferreira, Eva Longoria, and a whole lot more.

The party was held at private members' club Oswald's in London ... and Victoria posted it was the "Best night ever!"

And, shoutout to David for spicing up our lives!