"Hey @BarackObama," Bynes, 26, tweeted Tuesday evening. "I don't drink. Please fire the cop who arrested me. I also don't hit and run. The end."
The former child star of Nickelodeon's "All That" and "The Amanda Show" was not present when attorney Richard Hutton entered her plea in Beverly Hills Superior Court, E! News reported. A pretrial conference has been set for July 18.
On Tuesday, the Los Angeles district attorney's office had formally charged Bynes with a misdemeanor count of DUI. She had been driving her black BMW on April 6 when it hit the right rear panel of a Los Angeles County Sheriff's Department cruiser, causing minor paint damage to both cars, according to reports. The officer at the scene arrested her about 3 a.m. for driving under the influence, and Bynes was issued a citation after being booked at the West Hollywood sheriff's station, reports said.
The district attorney also charged Bynes with refusing an officer's request to test for substances in her system.
The actress has had a series of minor traffic incidents in recent months.
The president has not replied to Bynes' tweet.