Hard-partying actress Lindsay Lohan has checked into rehab, after pictures emerged on the Internet of her slumped over in the passenger seat of a friend's car.

Lohan, roughly a month shy of turning 21, "admitted herself to an intensive medical rehabilitation facility" on Monday, her publicist Leslie Sloane Zelnick said in a statement.

Zelnick also said that "it is our hope that the press will appreciate the seriousness of the situation and respect the privacy of Lindsay as well as the other patients receiving treatment at the facility."

The images showing Lohan in her friend's car were posted on X17online.com, and purportedly taken early Monday morning at a gas station after she left the Roosevelt Hotel in Hollywood, Calif.

In the photos, Lohan appears to be asleep with her mouth wide open and her head slouched back. She is pictured in a grey hooded sweat shirt and in one photo a red cut can be seen on her hand.

Another photo shows her kneeling on the ground with her back to the camera as a large man tries to assist her.

On Saturday, Lohan was arrested after an early morning incident in which her convertible car struck a curb.

Lohan and two other people were in the car, and Sgt. Mike Foxen said it appeared Lohan was speeding.

Los Angeles police announced at a news conference Saturday afternoon that officers found a "usable amount" of a drug in the actress' 2005 Mercedes SL-65, which crashed on Sunset Boulevard around 5:30 a.m.

Officers at the scene said the "usable amount" was tentatively identified as cocaine, said Lt. Mitch McCann. He said Lohan was not carrying the substance on her.

After the accident, Lohan was driven in another car to a hospital for treatment of minor injuries. Police arrested Lohan at the hospital for investigation of misdemeanor driving under the influence of alcohol or drugs.

She was released from custody because she was admitted to the hospital, police said.

In 2005, Lohan's vehicle struck a minivan carrying paparazzi who were on her tail after a meal at a Los Angeles restaurant.

Lohan will turn 21, California's legal drinking age, on July 2.

She has starred in such films as "Georgia Rules," "Mean Girls," and "Bobby."

With files from The Associated Press