Troubled actor Robert Downey Jr. pleaded not guilty to felony drug charges yesterday as defense lawyers shot down reports that their client teeters on the brink of suicide.

Downey, flanked by three defense lawyers, alertly answered all questions from Judge B.J. Bjork as he entered his plea in Riverside County Court. 

Downey, wearing a black sport coat, black T-shirt, black slacks and black shoes, exited a back door and fought through a crush of camera crews without answering any questions. 

Two associates rushed Downey, 35, to the back seat of a blue Chevy Monte Carlo and drove him away. 

If convicted of two felony counts for allegedly possessing cocaine and Valium and a misdemeanor charge of being high when cops busted him Thanksgiving weekend, the one-time Oscar nominee and current guest star on Ally McBeal faces a maximum sentence of 56 months behind bars. 

Defense lawyers Daniel Brookman and Robert Waters rejected British press reports that Downey's pals are worried he's suicidal. The actor, free on $15,000 bail, spent Christmas weekend with his 7-year-old son, Waters said. 

"Mr. Downey is very optimistic. He's upbeat about this," Brookman said. "He's committed to moving on with his life." 

It's been reported that Downey was despondent about being separated from his son over Thanksgiving weekend when cops - acting on an anonymous 911 call - raided his room at a posh Palm Springs resort on Nov. 25. 

Past drug problems and probation violations landed Downey in prison for one year, before his release in August. 

While Riverside County Deputy District Attorney Patricia Kelly would not comment specifically on talks with defense lawyers, she hinted that a deal could be in the works to put Downey in drug treatment — and, perhaps, kept out of prison. 

"Hypothetically, that would be the best situation" Downey could realistically expect, Kelly said. 

Downey's not-guilty plea opened a one-month window that requires prosecutors and lawyers of suspected nonviolent drug users to start negotiating a plea-bargain. If there's no deal by Jan. 29, Bjork is expected to set a preliminary hearing and push the case closer to trial. 

Kelly, her courthouse's primary narcotics prosecutor, said that about 70 percent of these nonviolent drug defendants end up cutting a deal. 

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