Paris Hilton & Kelly Osbourne Coachella beef: 'Fashion Police' starlet reignites Twitter feud with 'grow up' tweet after VIP 'b*tch' diss

Apparently, Kelly Osbourne and Paris Hilton crossed paths at this year's Coachella Music & Arts Festival - and things weren't too pretty...

On Sunday (April 13), the "Fashion Police" starlet sent out this heated tweet:

@KellyOsbourne: "@ParisHilton please grow up there is no need to act like a child you could of happily joined us! it's not 2005 no one cares!"

The post has since been deleted.

Everything allegedly started with a not-so-friendly interaction at a VIP area during the festival. Hilton wanted to join the festivities with Osbourne's crew, but she was turned down. The infamous Hollywood socialite then supposedly called Osbourne a "b*tch" (via The Daily Mail).

Things haven't escalated on Twitter (yet), but apparently 29-year-old Osbourne and 33-year-old Hilton continue feuding "privately." A tabloid source reveals:

"As far as Kelly is concerned, this is something out of nothing. Paris is being ridiculously sensitive and attention-seeking. Kelly was sitting with some mates, minding her own business, when Paris suddenly started b*tching and moaning, and sl**ging her off... She was asked by someone else to join the group, but declined and swanned off. The pair didn't speak for the rest of the weekend."

Years ago, Osbourne and Hilton were ultimate "frenemies." Back in 2005, the Black Sabbath offspring accused the millionaire princess of "being a bad influence on prepubescent teenage girls." Then she got mad when Hilton's then-boyfriend Stavros Niarchos allegedly "ruined" her 21st birthday in Las Vegas by trashing her hotel room.

Things were later resolved, with Osbourne saying - "We have fun together. I know that whatever I tell her, she tells everyone anyway, but I've always known she's not the friend that you tell your deepest secrets to. She's a fun person, and there is a sincerity about her."

Well, apparently the fighting words are back thanks to Coachella! Hilton has yet to respond on Twitter - she continues just having a good time.

So how about it - Team Osbourne or Team Hilton?