Lindsay Lohan sunglasses blonde court

Lindsay Lohan has arrived at the Airport Branch Courthouse in Los Angeles... after reportedly failing an alcohol test.

Lohan, who has been under house arrest, was sentenced back on April 22 to 120 days in jail for violating her probation.

Wearing black pants, a button up shirt and her blonde hair in a ponytail, showed up at the Airport Courthouse at 9:45am ... ahead of her scheduled 10am arrival.

Watch video of her arrival below!