Lindsay Lohan was dating Heath Ledger when he died, her mother has claimed.

Dina Lohan alleges the "Mean Girls" actress was romantically involved with the "Dark Knight" star when he died of an accidental drug overdose in January 2008 and has never fully recovered from his death.

Dina told Lindsay's father Michael in a leaked phone call published on Radar Online: "And she was dating Heath when he died? I don't know if you know that, but I know because I would drop her off and they were friends, very, very close, ok?"

Dina, who is divorced from Michael, fears Lindsay’s reaction to Heath’s tragic death is the cause of her many personal problems and may eventually prompt her to accidentally take her own life.

She said in the 2008 phone call: "When she's drunk or takes an Adderall with it she will do something like Heath Ledger did in a second without thinking.

"His death f***ed her up."

When Heath died it was revealed Lindsay had been left crushed by the news and had told friends she loved him.

Meanwhile, the actress recently left a friend’s birthday party in tears due to her relationship woes with on again, off again girlfriend Samantha Ronson.

A fellow partygoer at Los Angeles nightclub Crown Bar said: “She was happy for most of the night chatting with her friends, then the texting and emailing started and she was preoccupied for ages. At one point Lindsay walked to the other side of the club by herself, totally engaged with her phone.

“One second she was smiling and the next second she just flipped out and left really fast. Her emotions are all over the place. Lindsay is a total mess and still going back and forth with Samantha.”