Sia has offered up her support to FKA Twigs as she sues Shia LaBeouf for "relentless abuse", revealing the actor "conned" her into an adulterous romance.

Singer and performance artist FKA Twigs, real name Tahliah Barnett, filed suit against Shia on 11 December, claiming he was abusive towards her throughout their relationship, and now the Chandelier singer is chiming in with her experiences with the Honey Boy star.

"I too have been hurt emotionally by Shia, a pathological liar, who conned me into an adulterous relationship claiming to be single," Sia tweeted over the weekend, including a link to The New York Times report about Barnett's lawsuit.

"I believe he's very sick and have compassion for him AND his victims. Just know, if you love yourself - stay safe, stay away," she advised.

Sia, who recruited LaBeouf for her 2015 video Elastic Heart, added: "Also I love you @fkatwigs. This is very courageous and I'm very proud of you."

Twigs responded on Sunday, tweeting: "I'm sorry @Sia this reinforces why I had to publicly share my experience. We need to support each other... Love you back @Sia you're an inspiration and thank you everyone for your love and solidarity (sic)."

Shia has released a statement about FKA Twigs' lawsuit, writing: "I'm not in any position to tell anyone how my behavior made them feel... I have no excuses for my alcoholism or aggression, only rationalizations."

He conceded: "I have been abusive to myself and everyone around me for years. I have a history of hurting the people closest to me. I'm ashamed of that history and am sorry to those I hurt. There is nothing else I can really say."

However, Shia also insisted, "Many of these allegations are not true," adding he is currently in therapy and "committed to doing what I need to do to recover".

"I will forever be sorry to the people that I may have harmed along the way," he said.