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Actor Charlie Sheen pleaded not guilty to domestic violence charges on Monday, nearly three months after his wife told Colorado police in a 911 call he put a knife to her throat and threatened to kill her.

Sheen showed little emotion and said nothing during his brief arraignment in Pitkin County District Court. The plea was entered by Richard Cummins, a Colorado attorney who represents Sheen.

No new details emerged about the Dec. 25 incident.

The star of "Two and a Half Men" on CBS is charged with menacing, criminal mischief and assault. Menacing, the most serious charge, carries a possible sentence of one to three years in prison.

A judge scheduled a jury trial for July 21.

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Sheen is accused of assaulting Brooke Mueller Sheen at an Aspen home while they were on vacation. Charlie Sheen told police they were arguing but denied threatening to kill her.

In court, Sheen wore a black suit, white shirt and black tie. He chatted with a deputy and sipped water from a cup before the hearing started.

Afterward, he walked a few steps to the prosecution table and shook hands with Deputy District Attorney Arnold Mordkin.

Sheen, Cummins and attorney Steve Cochran of Los Angeles did not comment as they left the courtroom.

"I think the plea speaks for itself," Cummins later said by phone.

Stan Rosenfield, Sheen's agent, said, "Charlie is looking forward to the opportunity to clear his name."

It wasn't clear if a plea deal had been ruled out. Before the hearing, Mordkin said, "We always remain open. You never know."

Defense lawyers didn't address the issue.

Brooke Sheen told police her husband threatened her after she told him she wanted a divorce.

Sheen denied threatening his wife with a knife or choking her. He told officers they had slapped each other on the arms and that he had snapped two pairs of her eyeglasses in front of her, according to an arrest warrant affidavit.

Within a week of Sheen's arrest, attorneys for both husband and wife said the couple wanted to reconcile. Sheen's attorney asked the judge to modify a restraining order -- standard in Colorado domestic abuse cases -- that kept them from contacting each other.

On Feb. 8, the judge agreed, and the couple reunited and hugged in an Aspen courtroom.

Yale Galanter, Brooke Sheen's attorney, said it was too soon to say whether she would take the stand if the case goes to trial.

Galanter declined to comment on the possibility of a plea deal but said Brooke Sheen still wants the charges against her husband dropped.