CLAIRE DANES and Damian Lewis play star-crossed lovers in “Homeland,” but their real-life chemistry has gone PFFFT!

The tension between the Emmy-winning actors is evident as the hit Showtime series shoots its third season on location in North Carolina. Claire, 34, plays bipolar CIA agent Carrie Mathison on the show, while Damian, 42, is prisoner-of war-turned-sus­pected terrorist Nick Brody.

“Claire and Da­mian really got along for most of the first two seasons, but lately they seem to get on each other’s nerves – and then some,” a source confided.

Then new season opens during the aftermath of the horrific car bomb that decimated U.S. intelligence and prompted a global manhunt for Brody, who swears he had nothing to do with the terror attack. Lewis has already hinted that this will probably be the last season for his character.

Behind the scenes, a lot has changed for Claire in recent months. She and her hubby, actor Hugh Dancy, welcomed their first child, son Cyrus, in De­cember, and she’s now trying to juggle work with motherhood.

“As a first-time mom, she’s understandably stressed out,” noted a friend. “She basically just wants to get her scenes done and get back to little Cyrus. But Damian is very light-hearted, always joking around with the film crew and getting his picture taken with the locals when they’re on location. And that’s caused a lot of friction between him and Claire.”

Producers are hoping the bad blood doesn’t cause a distraction on the set, and they’re relieved the third season’s story lines will keep their characters far apart.

“It’s ironic – a lot of people fell in love with ‘Homeland’ because of the amazing chem­istry Claire and Damian have on-camera,” said the source.

“Maybe it’s good they aren’t working together much this season, because that chemistry is in short supply now.”