Alidousti objected to the execution of Mohsen Shekari who was found guilty of moharebeh, or fight against God, at a court in Tehran.
Tasnim News Agency, accused the actress of “spreading lies, instigating riots and supporting counter-revolutionary groups”.
An Iranian film-maker in a tweet also confirmed Alidousti’s arrest. Somayeh Mirshamsi said she had no information about which organ was behind the detention.
Several other actresses were also arrested in the wake of protests in Iran over the death of 22-year-old Iranian girl Mahsa Amini in police custody 3 months ago. But they were released on bail.