Britney Spears Took Field Sobriety Tests, Suspected of Drugs & Alcohol, CHP Says

Britney Spears was arrested for DUI last night ... and now TMZ has more details about the pop superstar's run-in with the law.

California Highway Patrol tells TMZ ... at approximately 8:48 PM Wednesday, a black BMW 430i was reported for driving erratically at a high rate of speed southbound on Interstate 101.

We're told officers located the car on the freeway, and when the driver pulled off the 101 at Westlake Boulevard in Thousand Oaks, officers identified her as Britney Spears.

According to CHP, Spears "showed signs of impairment" and submitted to a series of field sobriety tests. She was then arrested for "driving under the influence of a combination of drugs and alcohol," and booked into the Ventura County Main Jail.

The incident is still under investigation and chemical tests are pending.

As we reported, Spears was released from jail around 6 AM today, according to Ventura County inmate records.

The 44-year-old Grammy winner has had a drug-addled past. In a 2007 custody battle with ex Kevin Federline, a judge found "there is a habitual, frequent, and continuous use of controlled substances and alcohol by" Spears. 

Since then, the "Toxic" singer has sought mental health treatment through multiple rehab stints.