The 'Wannabe' hitmaker has no plans to rejoin the girl group to mark their big anniversary but admits there was a point where she considered being a part of the celebration.
When asked if she'll be making a Spice Girls comeback alongside her fellow bandmates, she said: "Good luck to them. I'm very grateful to whoever decided to make a big deal of Wannabe's anniversary, but it's now become this ridiculous thing.
"We all enjoyed playing at the Olympics in 2012. OK, Victoria not so much. I think she found that type of attention overwhelming ... The rest of us agreed to keep the door open. We said in a year or so we'd get together to see what we thought but we never got around to organising anything and by the time talk of the anniversary came round I'd decided against it."
And the 42-year-old singer also revealed she has a "real problem" with the idea of celebrity and fame.
She added to The Times newspaper: "As a Spice Girl, of course I was a celebrity, but in the past five to ten years I've had a real problem with what celebrity entails. It has become grotesque. I genuinely can't bear it."
Meanwhile, Mel previously admitted she wishes the group could be remembered for what they have achieved rather than others wishing for a reunion.
She explained: "The fascination with the band never seems to go away. It's a blessing and a curse all at the same time. Daily I'm asked 'are the girls getting back together?' Then it's When? How? Why? When we reunited in 2007 the questions stopped momentarily. We had done it - the fans were happy and we were happy. But the minute that tour ended it started again.
"Look, I will be a Spice Girl until I die. But the continuous speculation on whether we will reform to celebrate 20 years of 'Wannabe' has been particularly exhausting. Don't get me wrong - I totally get it. But is it a new rule that bands have to reform? Why can't we just be remembered for our incredible achievements in the nineties?"