Sia has claimed that she was once in "an adulterous relationship" with the actor Shia LaBeouf.

The singer's revelation came in support of fellow artist FKA Twigs, who has filed a lawsuit against LaBeouf alleging sexual battery, assault and emotional distress while they were in a relationship.

In 2015 LaBeouf appeared in the video for Sia's song 'Elastic Heart' at a time when he was in a relationship and she was married.

"I too have been hurt emotionally by Shia, a pathological liar, who conned me into an adulterous relationship claiming to be single," Sia, 44, wrote on Twitter. "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 added: "Also I love you ⁦@FKAtwigs. This is very courageous and I'm very proud of you."

LaBeouf has yet to respond to the latest allegations.