The scruffy, bearded man, thought to be in his 30s, was spotted acting suspiciously outside the Body Maxx Health Club in Beverly Hills and allegedly confronted the 28-year-old actress as she left the building, reported TMZ online.
Police were called to the scene and the suspect, whose identity has not been released, was taken in to custody.
"The call for service came out because the individual is affiliated with a stalking investigation. Sounds as if there has been some prior contact with this person," said a representative for the Los Angeles Police Department.