Amanda Bynes has been formally charged with a DUI Wednesday after her arrest in April.

The former Nickelodeon actress was taken into custody in Santa Monica, Calif. on April 6 after striking a Los Angeles County sheriff's cruiser with her black BMW. Bynes refused to take a Breathalyzer or a blood-alcohol test, which resulted in an additional charge this week.

The 26-year-old actress vehemently denied drunkenness following her arrest, and even pled her innocence to President Barack Obama.

"I don't drink," wrote Bynes on her Twitter account, directed toward Obama's presidential campaign. "Please fire the cop who arrested me."

Bynes' father, Rick Bynes, also contended that the 26-year-old was sober after revealing that the actress does not drink, according to People magazine.

"She was upset and emotional," explained Bynes of his daughter's driving incident.

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If convicted on the DUI charge, Bynes could face a maximum penalty as a first-time offender of 48 hours in jail, three years probation, and a nine-month alcohol program. She could also lose her driver's license for a year.

The April arrest marked the first of several driving mishaps for the actress. Recently while texting, Bynes accidentally backed over a curb before going out to a West Hollywood nightclub.

Also, two weeks after her arrest, the "All That" star was spotted making a slow three-point U-turn that delayed traffic.

Bynes, who has not appeared in an acting role since 2010's "Easy A," got her acting start in the 1990s. The California native was named by Forbes as the fifth highest-paid celebrity under 21 in 2007.

She starred in Nickelodeon's "What I Like About You" and later appeared in the film adaptation for the musical "Hairspray."

In June 2010, Bynes announced that she was retiring from acting via Twitter.

"I don't love acting anymore, so I've stopped doing it," she wrote. "I know 24 is a young age to retired but you heard it here first I've #retired."

A month later, Bynes changed her mind, posting, "I've unretired."