Courtney Cox big family secret!

Courtney Cox plans to reveal a huge family secret when she traces her ancestry in an episode of Who Do You Think You Are?.

The Scream 4 star was approached to appear on the program by her formerFriends costar Lisa Kudrow, who is an executive producer of the NBC show.

She has yet to film her episode but has been told to expect a big surprise as staff have uncovered a fascinating secret in her family tree.

“Lisa asked me to be on it; apparently they’ve found something in my family history which they won’t tell me because they like to surprise the person. It’s an amazing show…”

Meanwhile, Cox is reportedly dating her Cougar Town costar Josh Hopkins and her estranged husband, David Arquette, is devastated, sources say.

According to American tabloid the National Enquirer, Courteney and Josh behaved like one big happy family while vacationing with her daughter Coco.

“David is heartsick,” a source said.

“He and Courteney had been discussing reconciling, but that’s off the table now. It’s obvious that Josh has captured Courteney’s heart.

“Courteney, Coco and Josh have been carrying on like a family, while David is beyond distraught over the romantic development.

Cox and Arquette announced their separation in October after 11 years of marriage, and David entered rehab shortly afterward. They haven’t yet filed for divorce.