NBC is to make a US version of the hit BBC genealogy series Who Do You Think You Are?, which will be co-executive produced by Friends star Lisa Kudrow.

Producers are researching the family trees of several interested candidates to see if they have compelling enough backgrounds.

"It's great storytelling, a journey of self-discovery for these celebrities and truly moving and life-changing," the NBC executive vice-president of alternative programming, Craig Plestis, said. "You often see a very different side of them."

Who Do You Think You Are? launched on BBC2 in 2004 and will air its fifth series this year on BBC1.

The fourth series launched last summer with it highest audience ever - 6.8 million viewers - tuning in.

International versions of the format are also in production in Canada and Australia.