Lisa Kudrow recently previewed the new season of TLC’s celebrity genealogy documentary series Who Do You Think You Are? for TV Guide.

The season, which kicked off on Wednesday with an episode about former Sex and the City star Cynthia Nixson’s great-great-great grandmother, will feature Valerie Bertinelli, Jesse Tyler Ferguson, Lauren Graham, Kelsey Grammer, and Rachel McAdams.

Who Do You Think You Are? is an adaptation of the British series of the same name that has aired on the British Broadcasting Corporation (BBC) for 11 seasons.

The US version of the series premiered on NBC in 2010 and ran three seasons before being canceled by the network in 2012.

The series was subsequently picked up for a fourth season by TLC and in June the network renewed the series for a six-episode fifth season.

Season four set a strong precedent with celebrities such as Christina Applegate, Kelly Clarkson, Cindy Crawford, Zooey Deschanel, Chelsea Handler, Chris O’Donnell, and Trisha Yearwood.

Join our family tree–the season premiere of @wdytya is TONIGHT 9/8c! http://t.co/d085Gy6Oee pic.twitter.com/spItVvRDhU

— TLC Network (@TLC) July 23, 2014

In the first episode of season five, Cynthia Nixson discovers that her great-great-great grandmother was a victim of domestic violence and, in an act of self-defense, killed her husband with an ax.

“Real life is much more riveting and powerful. We were bug-eyed by that story!” Kudrow said.

She went on to reveal that three more season five celebrity guests – Bertinelli, Ferguson, and McAdams – had a murderer in the family.

Not all the #wdytya eps have a murder like next week too, but an oddly high # this season.

— Lisa Kudrow (@LisaKudrow) July 24, 2014

Kudrow said it’s not unheard of for a celebrity to back out due to the personal nature of the information uncovered by the show:

“…and we respect that. Sometimes they’ll talk to their family and the family says, ‘Nope. Not for us.'”

Martha gets a clean slate and can "launch a new life". Now Cynthia is traveling to her final resting place. What an amazing story. @wdytya

— Dan Bucatinsky (@danbucatinsky) July 24, 2014

Kudrow serves as executive producer of the series along with former Scandal star Dan Bucatinsky. Along with Don Roos (Boys on the Side, Marley & Me, Single White Female) Kudrow and Bucatinsky comprise the production company Is or Isn’t Entertainment.

The company’s first television series, The Comeback, aired for one season on HBO and starred Kudrow and Malin Akerman (Couples Retreat, The Proposal, 27 Dresses.) The series received three Primetime Emmy Awards, including Outstanding Lead Actress in a Comedy Series for Kudrow.

“If they had left it on, it would have been fine. Because I think in a couple of years, TV caught up to it,” Kudrow said of the series.

Get out your highlighters, gang. #TheComeback #BTS pic.twitter.com/jZ5PiKrYSb

— The Comeback (@TheComebackHBO) July 18, 2014

Those words proved true earlier this year when HBO revealed it would bring the show back almost ten years later for a six-episode second season.

In 2008 Is or Isn’t launched the web series Web Therapy with Kudrow and Bucatinsky starring as an Internet therapist and her assistant.

In the summer of 2011 the series transitioned from the Internet to television in the form of a half-hour Showtime series.

“I feel like we snuck in through the back door, almost [like] being a recurring character that finally becomes a regular. So that was easy. Painless, sort of,” Kudrow has said of the transition process.

In January the network announced it would renew the series for a fourth season, set to premiere in October.

Image via Wikimedia Commons