NEW YORK -- Confusion surrounded presidential candidate Mike Huckabee's appearance on Jay Leno's show and Hillary Clinton was set to appear with David Letterman as television's late-night funnymen prepared to return to the air Wednesday night.

Clinton was to join Robin Williams as Letterman's first guests as five late-night shows came back to the air following two months off because of the writers strike, according to a source close to the CBS show who spoke on condition of anonymity.

Meanwhile, GOP hopeful Huckabee appeared confused over which of the two late-night hosts had reached a separate deal with the union representing striking writers.

Huckabee said he supports the writers and did not think he would be crossing a picket line, because he believed the writers had made an agreement to allow late-night shows on the air. That's not the case with Leno, and picketers outside Leno's Burbank, Calif., studio targeted Huckabee.

"Huckabee is a scab," read one sign held by a picketing writer.

A "Tonight" show spokeswoman said she believed Huckabee would still be appearing with Leno on the eve of the Iowa caucus.

Letterman and fellow CBS host Craig Ferguson struck deals to allow writers to come back to work on Wednesday. Letterman's production company, Worldwide Pants -- which also owns Ferguson's show -- reached a separate deal with the writers on a contract on Saturday.

NBC's Leno and Conan O'Brien and ABC's Jimmy Kimmel were back at work Wednesday without writers.

O'Brien will play host Wednesday to comedian Bob Saget.

NBC's Carson Daly returned to his late-night show in December without writers.

In a letter to members, the WGA said, "It's a difficult and painful decision," but it'll have pickets outside the studios where Leno, O'Brien and Kimmel do their shows.

The guild said that Leno, O'Brien and Kimmel "are all members of the Guild and have been and continue to be extremely supportive" of the strike and their writing staffs.

So, the guild said, their "picket will not be of the hosts themselves but the companies for which their shows are produced."

Meanwhile, the deal struck by Letterman's company with the WGA has fallen into favor with the Screen Actors Guild. The guild's president issued a statement encouraging that members visit Letterman's and Ferguson's shows.

"Screen Actors Guild members will be happy to appear on the 'Late Show' with David Letterman and the 'Late Late Show' with Craig Ferguson with union writers at work and without having to cross picket lines," SAG president Alan Rosenberg said.