The storied rivalry between Jay Leno and David Letterman takes a new twist on Wednesday when the two stars of U.S. late-night television return to the air two months into a bitter strike by TV and film writers.

Letterman, who has lagged behind Leno in the ratings since 1995, has a chance to regain the upper hand as he ventures back with his writing team, and the blessing of the Writers Guild of America, under a special deal between the union and his production company.

That agreement, announced last week, enables Letterman to return with a full complement of monologue jokes and comedy bits, including his nightly Top 10 List, and makes it easier for him to book guests who otherwise might have balked at crossing picket lines to appear.

Leno will not have his writing team back and could face trouble getting celebrity guests who are members of the Screen Actors Guild.

On Monday, CBS announced the first guest on Late Show with David Letterman would be actor Robin Williams, followed the next night by Ellen Page, the Canadian star of the art-house movie hit Juno.

NBC's The Tonight Show With Jay Leno has so far announced only Republican presidential candidate Mike Huckabee as its first guest.

The two shows were thrown into immediate reruns when the WGA went on strike against major studios on November 5. The contract dispute, Hollywood's worst labor clash in 20 years, has hinged on disagreement over how writers should be paid for work distributed over the Internet.

Leno, Letterman and other late-night stars resisted pressure to renew production for weeks, even as ratings for reruns of their shows plunged. They began planning to return when talks to end the walkout collapsed on December 7.

Letterman was able to cut a deal with the WGA for his show and The Late Late Show with Craig Ferguson, which airs on CBS in the time slot following his own, because both programs are independently produced by his company, WorldWide Pants Inc.


Letterman also scored union points as an outspoken critic of studio executives involved in the WGA talks, describing them on his show as cowards, cutthroats and weasels.

Letterman's NBC counterparts -- Leno and Late Night with Conan O'Brien -- will be at a marked disadvantage having to cross picket lines and renew broadcasts without their writers. The same is true for ABC's Jimmy Kimmel Live.

The most obvious difference between them and CBS's shows may be in the caliber of celebrity guests they are able to attract.

Some stars, especially those who belong to the WGA's sister union, the Screen Actors Guild, are likely to boycott the NBC and ABC shows in support for striking writers.

By contrast, SAG President Alan Rosenberg said his union's members will be happy to appear with Letterman and Ferguson.

Problems booking celebrities would prove especially painful for Leno, O'Brien and Kimmel. They are barred by strike rules from preparing scripted material for their shows that union writers would normally produce, so presumably they will need to fill more time with guests than Letterman.

The strike adds a new dynamic to a Leno-Letterman rivalry that dates to Leno being chosen over Letterman, then NBC's late, late-night host, to take over The Tonight Show after Johnny Carson retired in 1992.

Letterman jumped to CBS and outrated Leno for the first two years. But Leno's populist tone propelled him to the top of the pack, even though critics generally prefer Letterman.