Ebert, who is negotiating a new contract with the syndicated TV show's distributor, Disney-ABC Domestic Television, is a copyright holder on the signature "thumbs up-thumbs down" judgment that's part of each film review. He has "exercised his right to withhold use of the 'thumbs' until a new contract is signed," the Walt Disney Co.-owned company said in a statement released Friday to The Associated Press. Health problems have kept Ebert from appearing on the show for more than a year, with guest hosts filling in. In the new season starting this weekend, co-host Richard Roeper will be joined for the first few months by movie critic Robert Wilonsky of the Dallas Observer.

Two episodes have been filmed so far without the catchy thumb assessment, which has become a staple of movie marketing and, in turn, a big part of the show's influence. Major releases including "Superbad" and "The Bourne Ultimatum" boast in newspaper ads published Friday of receiving "two big thumbs up" from the show, and at least five other films cite their favorable thumb treatment.

Ebert, 65, holds the copyright to the critique with the estate of Gene Siskel, his original co-host. Ebert, a film critic at the Chicago Sun-Times since 1967, and Siskel, who was at the rival Chicago Tribune, launched the show in 1975. Siskel died in 1999.