The kings of late night went back to work Wednesday night, some with and others without their regular writing staff.

David Letterman's "Late Show" started with a bearded Letterman walking onstage where dancing girls held picket signs supporting writers on strike.

"Ladies and gentlemen, the only show on the air now that has jokes written by union writers," Letterman declared during his opening monologue, then added, "I know you're thinking to yourselves at home -- 'This crap is written?"'

Letterman was able to return to air with his regular writing staff after his production company, Worldwide Pants, reached an agreement last Friday with the Writers Guild of America.

Letterman was also able to welcome guest Robin Williams, who is a member of the Screen Actors Guild -- Hollywood's major actors' union. SAG has said its membership is permitted to appear on the Letterman show as well as Craig Ferguson's "Late Late Show'', which is also owned by Worldwide Pants.

Letterman's Top 10 list was a list of the writers' strike demands. It included such items as "Complimentary tote bag with next insulting contract offer" and "Hazard pay for breaking up fights on `The View.'"

Over on NBC's "Tonight'' show, host Jay Leno returned without any writers, as did fellow late-night hosts Jimmy Kimmel and Conan O'Brien, who was also sporting a beard.

"The Daily Show'' with Jon Stewart and "The Colbert Report,'' both of which air on CTV, are set to return on Jan. 7, also without striking writers.

Leno opened up with a monologue he said he crafted before the strike. According to a script provided to The Associated Press by NBC, Leno said his team was following the rules.

"We are not using outside guys," he said in the monologue. "We are following the guild thing ... we can write for ourselves."

Leno welcomed Republican presidential candidate Mike Huckabee as his first guest. He then had chef Emeril Lagasse and rapper Chingy.

O'Brien welcomed Bob Saget to pitch a new NBC show. Race car driver and "Dancing With the Stars'' champ Helio Castroneves went to Kimmel.

The Hollywood Reporter's Michael Rechtshaffen noted on CTV's Canada AM Wednesday that the strike has even made it difficult for the late night hosts to secure good guests.

"Because actors have said and made very clear, they don't like crossing picket lines," Rechtshaffen reports. "And if that's true, then Jay could have pretty slim pickings while Dave (Letterman) gets Robin Williams kicking the show off tonight and then he'll get all the other big 'A-listers'."

There were several fillers throughout the shows to make up for the loss of opening monologues and produced skits, which require writers to script.

Leno took questions from the audience while O'Brien showed off Christmas cards and tried to see how long he could spin his wedding ring on his desk. The hosts also spent some time paying homage to the writers' cause.

"The writers are correct, by the way. I'm a writer ... I'm on the side of the writers," Leno said.

O'Brien said: "I want to make this clear: I support their cause... These are very talented, very creative people who work extremely hard. I believe what they're asking for is fair."

Members of the WGA had promised to picket the Leno and Kimmel shows in Los Angeles Wednesday, while protesting the O'Brien program in New York.

One woman from Grimsby, Ont. said outside the NBC studios that she didn't expect she'd have to cross a picket line when she booked her tickets for the Leno's show.

"I do feel kind of guilty with all the people walking by with their signs," she told CTV News outside the show's studio.

In a Tuesday letter to membership, WGA East President Michael Winship said his membership is disappointed the shows are returning to air while the strike drags on.

"Leno, O'Brien and Kimmel are all members of the Guild and have been and continue to be extremely supportive of our strike and their writing staffs. For that we truly are grateful," Winship wrote.

"Nonetheless, they are coming back without writers and without a new Guild contract, forced back on the air by companies that refuse to sit at the table and bargain with us. We cannot let that pass."

Rechtshaffen says Leno was under strong pressure from NBC to return to air.

"Jay's been taking a real hit in the reruns. He's dropped about 40 per cent in the reruns, whereas Dave has dropped about 20 per cent. So they're anxious to get the new things out there," he says. "I mean, I feel for Jay, but the problem is NBC owns that show. There's nothing he could really do."

The writers' strike, Hollywood's worst labour clash in 20 years, has hinged on disagreement over a number of issues, primarily how writers should be paid for work distributed over the Internet.

Talks stalled on Dec. 7. Rechtshaffen reports that the strike could drag on for weeks - or even months - yet.

"What I hear is from friends and colleagues is that the producers are pretty much willing to sit tight until at least the end of February. So it could go on."

He says that could put the biggest award shows of the year - the Oscars and the Golden Globe Awards -- in serious jeopardy.

"Again, I have friends who are members of the Hollywood Foreign Press association. As of a week ago, they were saying there was talk within the group of cancelling the show (Golden Globes) altogether, cancelling the awards this year.

"There's other talk about 'Maybe we'll have the awards but not televise it.' Because if they're going to be picketing, which they say they are, there's going to be nobody wanting to cross the picket lines there. So what kinds of A-listers will attend the awards?

"However, there is a possibility that Dick Clark Productions, which produces the show, and the Hollywood Foreign Press, which owns the show, could make that kind of deal with the Writers Guild like Worldwide Pants, Dave's company, made with the guild."

With files from The Associated Press and a report from CTV News' Tom Walters