Josh Brolin on His New Year's Arrest, Nick Nolte's Weird Robe

Josh Brolin and Sean Penn

Co-stars Josh Brolin (left) and Sean Penn pose outside Grauman's Chinese Theatre in Hollywood. Brolin plays Sgt. John O'Mara who heads up the team assigned to bring down gangster Mickey Cohen, played by Penn, in Ruben Fleischer's Gangster Squad. The duo previously worked together on Milk.

"New Year's, that's what happened."

So Josh Brolin explains his arrest just before midnight Jan. 1 after officers found him heavily intoxicated on a sidewalk in Santa Monica.

"I'm the one guy who's out there, and they go, 'Hey there, that's Josh, let's grab him!' It was New Year's, it was a pretty innocent thing, it was a fun thing," Brolin said Wednesday on Good Morning America.

"The most awful thing about it is you see this shot of me like this [furrows brow]," added the Gangster Squad actor, referencing his angry-looking, tough-guy mug shot. "They don't show you the other shot where I turn and I have a huge smile on my face. So it was, you know, whatever. They were very sweet to me actually."

PHOTOS: Ryan Gosling, Emma Stone and Josh Brolin Bring Glamour to the 'Gangster Squad' Premiere

Four hours after his 3 a.m. booking, Brolin was released from jail without a citation.

In Gangster Squad, which opens Friday, Brolin plays a leader of a crew of LAPD outsiders who try to take down mob king Mickey Cohen (Sean Penn). Ryan Gosling, Emma Stone and Nick Nolte also star. And funnily enough, Brolin brought up the weird yellow robe that Nolte wore to the film's Hollywood premiere on Monday. As The Hollywood Reporter pointed out, "he looks like Jean Valjean's troubled twin after a particularly rough night out with the Thenardiers."

"Did you see Nick Nolte came to the premiere .... he was in a robe. I don't know what Nick is really going through ever," joked Brolin, who went on to defend pal Penn from George Stephanopoulos' gentle mockery of the thespian-activist's deep tan.

"Can you explain what was behind his tan on the red carpet?" quoth Stephanopoulos, clearly alluding to this photo.

"I love that he came to the premiere with a tan," Brolin replied. "He's been really healthy, he's been running four miles a day, he's been in Haiti, he's been doing all these things. And, you know, he doesn't have time to put on makeup and go to a premiere so he just shows up."

Twitter: @ErinLCarlson