Former rap mogul Marion "Suge" Knight and comedian Katt Williams pleaded not guilty Tuesday to robbery charges filed against them after a celebrity photographer accused them of taking her camera last year.

The pair appeared briefly in a Los Angeles courtroom Tuesday and entered the pleas, which needed to be re-entered because a judge determined two weeks ago that they should stand trial for the September 2014 incident in Beverly Hills.

Los Angeles Superior Court Judge Ronald S. Coen on Tuesday admonished Knight because the Death Row Records co-founder had held up a sign conveying a happy birthday message to his son for cameras during his last court appearance two weeks ago.

"If he does it again, I will shackle his hands to a chair," Coen said. Knight, 50, acknowledged he understood the judge's warning.

Coen has taken a hard line with Knight, who had a series of medical episodes in court and refused to leave his cell for one hearing, prompting the judge to sign an order to have him forcibly brought to hearings if necessary.

Knight's attorney denies the Death Row Records co-founder was involved in taking photographer Leslie Redden's camera last year, just days after he was wounded in a nightclub shooting. His attorneys have cited the wounds as causing some of his courthouse medical episodes.