The fashion designer was joined by her family - including husband David and their four children Brooklyn, 25, Romeo, 21, Cruz, 19, and 12-year-old Harper - and friends at Oswald's in Mayfair, London, to celebrate the milestone and guests were treated to the group getting up on stage together for the first time since the London Olympics closing ceremony in 2012 to sing along to their hit single 'Stop', complete with original choreography.
David shared footage of the moment Victoria, Geri Horner, Emma Bunton, Mel B and Mel C sang together on Instagram and wrote: "I mean come on x @victoriabeckham @melaniecmusic @officialmelb @emmaleebunton @gerihalliwellhorner [green, yellow, red, purple, blue and white heart emojis] (sic)"
Insiders said having all her former bandmates at the party "meant the world" to Victoria, whose green dress from her own label was accessorised with crutches as she is still not recovered from a recent ankle injury.
A source told MailOnline: "It meant the world to Victoria that they were all there.
"They were a huge part of her life and they shared so much together.
"They were special days and so of course to have them there to mark her 50th was just wonderful for her. It made everything so perfect."
Other guests at the party included friends Tom Cruise, Eva Longoria, Salma Hayek, Gordon and Tana Ramsay, Marc Anthony, Guy Ritchie, Rosie Huntington-Whiteley and Jason Statham, but Brooklyn's wife Nicola Peltz Beckham was forced to miss the bash to be with her grandmother after her relative fell ill.
Partygoers were served "Italian inspired platters" to start ahead of main courses of steak and see bass, as well as £3,000 bottles of the birthday girl's favourite wine, Chateau Mouton Rothschild and £500 bottles of champagne, before hitting the dancefloor to music from DJ collective Hale Zero.
Victoria was presented with a huge birthday cake before David and all four children gave speeches.
A source told The Sun newspaper: "David really splashed the cash. He wanted it to be extra-special for her after she always makes such an effort for everyone else."