Johnny Depp was a "monster" who repeatedly beat his ex-wife Amber Heard during a series of drug-fuelled attacks before and during their marriage, new court documents claim.

The US actress alleged Depp, 55, left her fearing for her life after he choked her and ripped chunks out of her hair in more than a dozen violent altercations.

The details emerged yesterday as Heard, 32, asked a judge to dismiss a $50 million defamation lawsuit filed by Depp over an article she wrote in The Washington Post in December claiming to be a victim of domestic violence.

In the motion filed in a court in Virginia, Heard describes in extraordinary new detail how Depp repeatedly slapped, shoved, choked and pulled her hair before and during their two-year marriage.

Photographs showing Heard with bruises on her face and scars on her arms as well as newly released screenshots of text messages describing the incidents were produced as exhibits.