Kelly Osbourne told Paris Hilton to “grow up” after running into her on Saturday.

The E! host and Paris were both at the Coachella music festival in Indio, California and apparently got into a spat.

Kelly, 29, was reportedly hanging out with friends at one of the VIP areas when Paris came over.

The heiress apparently then glared at Kelly before stalking off and accusing her of being a “b***h”, according to UK newspaper The Mirror.

Kelly then took to Twitter and addressed Paris directly, accusing her of childish behaviour.

“@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!” said Kelly.

“As far as Kelly is concerned, this is something out of nothing. Paris is being ridiculously sensitive and attention-seeking,” a source told the newspaper. “Kelly was sitting with some mates, minding her own business, when Paris suddenly started b***hing and moaning, and slagging 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.”

This isn’t the first time Kelly and Paris have battled in public. Back in 2006, the 29-year-old daughter of Ozzy and Sharon Osbourne accused Paris of being a bad influence on young girls.

There was also an alleged incident when Paris’ then-boyfriend Stavros Niarchos trashed Kelly’s hotel room at her 21st birthday party in Las Vegas.

The two did make up later on – but clearly it didn’t last. “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,” Kelly said. “She’s a fun person, and there is a sincerity about her.”