Courtney Love on Cobain anguish

Courtney Love has seen the upcoming Kurt Cobain biopic three times and calls it "pure anguish".

Kurt Cobain: Montage of Heck was written and directed by Brett Morgen and premiered at this year's Sundance Film Festival.

It tells the story of the late Nirvana frontman, who killed himself in 1994 aged 27. Kurt was married to Courtney, and their daughter Frances Bean executive produced the project, which Courtney was touched by.

"It's very moving. I've seen it now three times, and I'm probably not going to see it again. It's too much," she told talk show host David Letterman. "The director, Brett Morgen, did a fantastic job on it. I trusted him completely... But I did trust him completely and gave him the keys to my storage and just said, 'Tell the truth.'"

Kurt was a heroin addict and Courtney has fought a battle with drugs too. The 50-year-old star discussed how she overcame her problems with the talk show host, explaining that chanting and Buddhism are the reasons she is clean today.

"What really saved me was, obviously going to meetings and stuff like that, but I'm a Buddhist. I chant and I'm really serious about it. I chant twice a day," she said.

"It changed my life. Absolutely. It turned everything around… [I chant] as much as I can... an hour... I try, I aim for that. It's like doing sit-ups, spiritual sit-ups."

Courtney famously fell out with Kurt's Nirvana bandmate Dave Grohl, but they are now back on good terms. They were pictured with each other when the band was inducted into the Rock and Roll Hall of Fame last year and Courtney is glad the bad times are behind them.

"I think you just get to an age where, 'Why are we suing each other? Really?'" she said. "It just got stupid. Honestly, me and Dave Grohl, we had some gnarly times over 20 years. And if we can make up, anyone can make up. We're really cool now."