The Brokeback Mountain actress was reported to be portraying the tragic 1960s rocker last month (Oct16) and has now confirmed the news, adding that the project is happening "as far as I know".

She admits she worked hard to get the job and now she's got it, she's beginning to freak out about taking on the responsibility of playing the icon.

"I figure there's one good day in the life of an actor, which is when you get the job," she told E! Online. "Before you get the job, you're like, 'Come on! I'm begging. I'm dying for this. I gotta have it! Please, I'll do anything. I promise... Take me! Take me!'

"You get the job and you're like, 'I got it! I'm so excited! I can't believe I have this opportunity. I can't believe I'm going to get to do this.' And then you start worrying the next day. I'm in the worrying-the-next-day phase."

The biopic is set to be directed by Sean Durkin and based on the book Love, Janis by the singer's sister Laura, which chronicles the letters the singer sent to family and friends throughout her career. Joplin died from a heroin overdose in 1970, aged 27.

This wouldn't be Michelle's first time playing a real person either - she portrayed tragic actress Marilyn Monroe in 2011's My Week with Marilyn - and she can also sing, which was most notably showcased in a recent Broadway revival of classic musical Cabaret.

A number of films about Joplin have been in the works for years. One project was due to be directed by Wild's Jean-Marc Vallee and star Amy Adams but that has been delayed due to legal issues, and another set to star Zooey Deschanel as the rock star also seems to be on hold.