If you’ve been wondering about Joaquin Phoenix’s reportedly erratic behavior on red carpets in recent weeks, will it comfort you to know that he’s just as extreme on the set? EW’s Chris Willman observed him during the filming of Walk the Line last year and found that stories of Phoenix’s insistence on staying in character all the time (he even made everyone on the set call him J.R., Johnny Cash’s real name) were true. To his credit, the actor explains his Method acting to Willman in the forthcoming issue. ”I’m embarrassed about it now,” he says, noting that his insistence made him look like a ”f—ing idiot,” especially to people who knew the real Cash. ”But when I heard ‘Joaquin,’ it just didn’t feel right. It’s not a brilliant method. It’s simply that I don’t know what I’m doing, and I use all the help I can get. It’s an act of desperation.”

addCredit(“Walk the Line: Suzanne Tenner”)

Conversely, once the shoot is over, Phoenix is just as quick to abandon a character and his associated behaviors. ”When I did Gladiator, I thought that I would carry a sword with me everywhere. When I did Ladder 49, I didn’t want to let go of my turnout gear, and I didn’t believe that I could go through life without smelling smoke. With this, I played the guitar all the time, and then left it. I picked it up a couple weeks ago and realized I’d forgotten how to make an A-minor.”

That must be vexing, terribly vexing.