Despite strict royal protocols, she insisted there'd been no fallout afterwards.
"I think he quite enjoyed it, so we didn't really get in trouble," Mel C said.
The former Spice Girl also opened up about the conflicting headlines surrounding the band's involvement in Prince Harry and Meghan Markle's wedding this weekend.
Over the past few months, there have been reports both suggesting they were all invited and set to perform — and contradictory claims that none of them were going.
And Mel C has finally set the record straight.
"We were never invited, we were never asked to perform. [The rumours] all started with an interview Mel B gave in America, and I think it started as a joke and gathered a bit of pace ... and the world's media went a bit bonkers."
She also believes 'Scary Spice' Mel B may have been trying to drop a big hint to the engaged royal couple.
"You know when someone really wants to do something, and they think, 'If I put it out there, maybe it'll happen?'"
Despite that, Mel C admitted she'd briefly wondered if she was the Spice Girl left out, after hearing her bandmate suggest she was invited.
"I was here in London and did the Prince's Trust Awards [in March] and Prince Charles was there and I felt like going, 'Oi! Where's my invite?'"
It comes after reports surfaced on Wednesday that Elton John was likely to perform at either the ceremony or reception — and that the Spice Girls had never been approached, although a select few had been invited to attend.
"Only Victoria, Emma and Geri were invited, so clearly, the Spice Girls were never going to perform," a source told The New York Post's Page Six.
