David Tennant to star in US comedy pilot

David Tennant, who leaves BBC TV's Doctor Who early next year as one of the most popular Time Lords in the show's long history, is to make his US television debut. While Tennant will be hoping to crack America, the ailing US network NBC is keeping its fingers crossed that it has a potential ratings-buster on its hands.

Tennant is taking the lead role in a pilot for a comedy legal drama, Rex is Not Your Lawyer. He will play a top Chicago lawyer who suffers from panic attacks and, as a result, coaches his clients to represent themselves in court.

The one-hour pilot will be directed and executive produced by David Semel, who directed the pilot for Heroes which went onto become a big hit.

Tennant, 38, was the 10th actor to play Doctor Who. His final episodes are in the can but not yet scheduled: they will either be screened some time this winter. He has been replaced by the 27-year-old actor Matt Smith, who has begun filming the next series.

Tennant, who became a household name in Britain when he landed the Doctor Who role five years ago, will be hoping the role can make him a star in America, perhaps emulating the success of fellow British actor Hugh Laurie.

Laurie has become one of the highest-paid actors in American television and has won two Golden Globes for his role in Fox's medical drama House.

But NBC has even more riding on the pilot. The network is currently ranked fourth among America's big four after receiving regular trouncings in the ratings. Last month, the New York Times reported, NBC's flagship Jay Leno Show was beaten by a repeat screening of CSI Miami on CBS and – even more humiliating - by Sons of Anarchy, a drama series about bikers on the cable channel FX.

According to the Hollywood Reporter, NBC has spent months searching for the right actor to play Rex before signing up Tennant. US media commentators and bloggers are now waiting to see if the Doctor can save NBC.