Embattled Hollywood star Armie Hammer is under police investigation after a woman alleged she was violently raped by the actor in 2017.

According to CNN, LAPD spokesman Officer Drake Madison said that Hammer is the main suspect in a sexual assault that was reported to police on February 3.

However, the police did not give any further details on the incident or who made the report.

The investigation came hours after a 24-year-old girl, who identified herself as Effie, came forward with her allegation of rape against Hammer.

During a virtual news conference with attorney Gloria Allred on Thursday, Effie said she had an on-and-off romantic and intimate relationship with Hammer from 2016 to 2020.

She was 20 when she met Hammer on Facebook, and she "fell in love with him instantly," she said.

Effie claimed that Hammer would often test her devotion to him and as time went on, he allegedly became "increasingly more violent", she added.

Recounting an incident that happened on April 24, 2017 in LA, Effie alleged that Hammer raped her for four hours, slammed her head against a wall and committed other violent acts against her.

"During those four hours I tried to get away but he wouldn't let me. I thought that he was going to kill me. He then left with no concern for my well-being," she said through tears.

In a statement through his lawyer Andrew Brettler, Hammer, 34, denied the accusations, terming them as "outrageous allegations".

The lawyer said all of Hammer's relations with the woman had been "completely consensual, discussed and agreed upon in advance, and mutually participatory".

Brettler also shared a screenshot of text messages purported to have been sent by the accuser that contained suggestions of extreme sexual behaviour.

He said Hammer had responded to the woman, making it clear that he did not want to maintain that type of relationship with her.

The actor found himself embroiled in a massive controversy after a series of his Instagram direct messages were leaked online by an unverified account.

These messages, some of which date back several years, detailed affairs, sexual misconduct and cannibalistic fantasies.

Hammer's former girlfriends have come on record with damaging allegations of sexual abuse and cannibalistic tendencies, leading to Hammer's departure from a series of high profile Hollywood projects such as series The Offer and film Shotgun Wedding