Kirsten Dunst is in rehab.

The 'Spider-Man' actress - whose partying lifestyle has lead to her being nicknamed 'Kirsten Drunkst' by gossip bloggers - has reportedly checked into Utah's Cirque Lodge facility to receive help for an unknown problem.

A source inside the facility told America's Star magazine: "She desperately needed help. She seemed to be intoxicated when she checked in because she was acting really erratic. She was extremely emotional, constantly breaking down in tears.

"She not in a good place right now, but thankfully, she's getting the help she needs."

Kirsten's self-committal comes after she behaved erratically at Utah's Sundance Film Festival.

A source said: "Kirsten is on the verge of a breakdown. She came late, left early and acted erratic at all the Sundance events."

Kirsten's spokesperson denied she acted strangely at the festival saying: "Kirsten is fine."

The 25-year-old actress is a keen supporter of the campaign to get marijuana legalized in the U.S.

She said: "I drink moderately, I've tried drugs. I do like weed. I have a different outlook on marijuana than America does." I've never been a major smoker, but I think America's view on weed is ridiculous. I mean - are you kidding me? If everyone smoked weed, the world would be a better place."

The Utah facility is popular among celebrities. Lindsay Lohan and Mary-Kate Olsen have both sought help in the treatment center, while 'Hitch' star Eva Mendes checked out yesterday after being treated for "some personal issues".