When M.I.A. played Coachella's main stage this year instead of her customary dance tent, it was because she was asked to be a last-minute stand-in for Amy Winehouse, who, not surprisingly, couldn't make it. M.I.A. told Spinner earlier this summer that, at that point, she didn't feel quite ready to storm a festival's main stage and that she preferred the dance tent anyway. She was up for the challenge of replacing Winehouse, however, and she certainly delivered.

She's not quite as forgiving of Tenacious D being brought in as a replacement for the Beastie Boys at Outside Lands. Perhaps her beef is more with the fact that now she'll be "opening" for Jack Black and Kyle Gass on Sunday instead of Mike D., MCA and Ad Rock. Either way, she took to Twitter to let her fans know how she really feels. "Can't believe they replaced Beasties with Tenacious D?" she tweeted in Kanye-style capital letters. "And if I pull out, they sue! So, really? Tenacious D after me?"

M.I.A. claims that she originally agreed to the show because the Beastie Boys were headliners and that now she'll just have to "go hard." We can only imagine what that means, but at Coachella she told the audience that she was going to bring the chaos from her dance tent routine to the main stage and, much to the chagrin of promoters and security, invited everyone to bum rush the stage. Naturally, the people didn't need to be told twice.

This time around, it appears as if M.I.A. is already planning a coup. "You're all welcome on stage from the get-go," she told her Twitter followers. "F--- it! I'm taking 'Bird Flu' out of the set! Just to make a point!"

Things are going to get interesting. Outside Lands starts Friday in San Francisco's Golden Gate Park with a fully-stocked line-up, anchored by Pearl Jam, Dave Matthews Band and now Tenacious D. We'll let you know how it goes.