AceShowbiz - Country star Tim McGraw and soul icon Lionel Richie are set to dig deep into their family roots after signing up for Lisa Kudrow's hit U.S. series "Who Do You Think You Are?". The singers will join Vanessa Williams, Kim Cattrall, Steve Buscemi, Rosie O'Donnell and Ashley Judd as guests on the family tree show.

And former "Friends" star Kudrow, who executive produces the programme, is delighted to see other celebrities interested in researching their ancestry. She says, "It's not just like you show up for a couple hours and you're done. It's kind of a commitment. So the people who want to do it are genuinely interested in finding answers to their questions."

The second season of the show will air on U.S. TV early next year. Actresses Susan Sarandon and Sarah Jessica Parker both uncovered mysteries about their family tree during the first series of the hit show.