The information comes from representatives for the film.
Jafar Panahi, director and co-writer, says in a statement that Mahmoudian is not just "a human rights activist and a prisoner of conscience."
"He is a witness, a listener and a rare moral presence - a presence whose absence is immediately felt, both inside and outside the prison walls," says Panahi.
Just a few days ago, Mahmoudian was one of 17 who signed a condemnation of Ayatollah Ali Khamenei's repression of protesters in Iran.
Panahi, who is not in Iran, also signed.
"It Was Just an Accident" is nominated in the categories Best International Film and Best Original Screenplay.
