Victoria Beckham, who currently runs a successful fashion label, agreed to sing at the London 2012 event on the condition that the other girls wouldn't push to reform again, the Daily Star Sunday reports.
> Spice Girls party after Olympics closing ceremony - pictures
Mel B was overheard saying seconds before they went on stage: "This is it girls, the last time - enjoy it."
A source explained: "Victoria loved one final swansong but that's it for her. All the girls had the most amazing night and I'm sure the rest could be persuaded to reform again."
Emma Bunton said of the performance: "We had the night of our lives. To get ready we were all listening to music and dancing around. It was like the old days again.
"By the time we went on we were so excited. The best thing has been the reaction from everyone. The support has been overwhelming and it's amazing to know people still care so much."
Mel C previously told Digital Spy that she wouldn't rule out a Spice Girls reunion, with sources suggesting they would consider reforming without Beckham.
Watch the Spice Girls performing at the London 2012 Olympics closing ceremony below: