Irish playboy Colin Farrell has reportedly focuses his attentions on a new target - Sean Penn's sexy wife Robin Wright PENN.

And sources say the DAREDEVIL hunk is right on track for landing in big trouble with Penn for his efforts.

A source tells American tabloid the STAR, "Everyone believes he has the hots for Robin - he can't stay away from her. But he better not forget who she's married to."

Tongues started wagging because of the time Farrell has been spending around Robin's trailer on the Toronto, Canada, set of their new film HOME AT THE END OF THE WORLD. Farrell also rides with her to the set each day in a minivan.

A Penn pal says, "Sean trusts Robin, but if Colin so much as looks at her in a way that he doesn't like or he feels is disrespectful, he'll be happy to straighten him out. He's not afraid to let his fists do the talking - and he has guns too."

But Farrell remains undeterred, say sources, who explain, "They shot a sizzling scene in which he kissed her tenderly among the trees. And when they shouted 'Cut', it was clear Colin didn't want to let go. As they stood around talking to the crew, he put his arm around her shoulder and looked intently into her eyes.

"Colin is crazy if he thinks he can target Robin as his next conquest. He'll have Sean Penn coming after him."