The Brit was too focused on making his directorial debut a success to worry about the risk to his marriage of having MACkie kiss his real-life partner Connelly.

The actors play homeless drug addicts in the new movie and Bettany admits he wanted them to look like a real couple on camera.

"You're a director so this lizard brain just kicks in for everything and I go, 'God, I hope they really kiss a lot!'" the first-time director explains. "There's this hateful monster that comes out of you.

"They were in this pool and the pool is really cold and Jennifer's going, 'Can I get out?' And you're going, 'No you can't, I haven't got the shot!' And she's begging me - 'Really? Really?' But I'm like, 'Stay in the f**king pool!' And I'm pushing her down, I'm ashamed to say."

And MACkie admits it was difficult filming scenes where he had to kiss the director's wife.

"There was the water sequence when we're in the waterfall and we kiss," he recalls. "So we do the first take and I'm, like, a little shy about it and Paul goes, 'Kiss her, mate!'"

MACkie also struggled during filming one day when an old friend spotted him on the streets of New York and felt sure the actor had fallen on hard times.

"We were shooting up in Harlem one day, on the sidewalk," The Captain America: The Winter Soldier star chuckles. "It's me and the guy who's supposed to be my friend and we were next to my alley by my character's stuff. And we're shooting and I hear, 'Yo, MACkie!' I look up and my friend has pulled his car over and he comes running over.

"It was pretty funny. He said, 'You need a (hair) cut. Why don't you come with me to the barbershop and I'll get you one?' I said, 'Dude, I'm in a movie!' Then he realised and said, 'Oh my bad! Ahright (sic), I'll see you later?'

"That was when I felt one of those moments when we were shooting that I must be doing something right because I must've really looked homeless!"