The Mean Girls star wrote “Alaikum Salam” on her Insnewsram bio – meaning “and unto you peace”.
The 30-year-old’s social media account is followed by 5.7 million people, with many commenting on her apparent conversion.
“I heard that Lindsay Lohan converted to Islam?” one user wrote. “If it’s true, alhamdulillah. God has shown her the right path to now follow.”
Posts on Lohan’s Twitter account have also apparently been erased, with the page showing only her bio.
One of the star’s followers posted photos of Lohan wearing a hijab during a visit to Turkey in October, writing: “May Allah bless you.”
Lindsay Lohan deleted all her pictures after converts to Islam with the caption ‘Alaikum salam’ on her instagram. May Allah bless you ☺ pic.twitter.com/Yk04HjxJo6
— goldilocks (@thepocahontas98) January 13, 2017
The actress penned a poem about the refugee crisis after her visit to Turkey.
“Sometimes I hear the voice of the one I loved the most / but in this world we live in of terror,” it reads.
“There has to be something I can figure out / rather than living in a world of fear and doubt / they now shoot, we used to shout / if only I can keep trying to fix it all.”
Lohan first prompted rumours of Islamic beliefs in 2015, when she was photographed holding a copy of the Koran while doing community work.
“We all believe in something and at the end of the day it all ties to a god or a spiritual adviser,” she said at the time.
Before turning to philanthropy, Lohan had been in and out of rehab for cocaine and alcohol abuse.