Brad Pitt and Gwyneth Paltrow during their relationship. Picture: Bang Showbiz

Brad Pitt threatened to kill Harvey Weinstein after he allegedly made unwanted sexual advances towards Gwyneth Paltrow.

The 45-year-old actress has previously told how the disgraced movie mogul tried to lure her into his hotel room and asked for a massage after she signed on to star in 'Emma' and 'Shakespeare in Love' in 1995, prompting her to confide in her then-boyfriend, and she still thinks he's "the best" for not being afraid to use his "fame and power" to warn the producer away from her.

Gwyneth told DJ Howard Stern that the 54-year-old actor - who she dated for three years until 1997 - approached Weinstein on the opening night of a Broadway production of 'Hamlet'.

She recalled: "He told me exactly what he said. He said, 'If you ever make her feel uncomfortable again, I'll kill you.' It was great.

"It was the equivalent of throwing him against the wall, energetically.

"He leveraged his fame and power to protect me at a time when I didn't have fame or power yet ... he's the best. I love him for this."

The 'Iron Man' actress was left "shaken" by her encounter with Weinstein and admitted she was initially hesitant to speak about her experiences when first approached by reporters.

But she added: "Now, it seems like a no-brainer, but at the time, the floodgates hadn't opened, and not only did the story break, but it changed the culture completely."

The Goop founder - who is engaged to producer Brad Falchuk and has children Apple, 14, and Moses, 12, with ex-husband Chris Martin - previously told her how Weinstein warned her not to tell anyone what had happened between them.

She said: "I thought he was going to fire me. It was brutal ... I was expected to keep the secret."

Weinstein has stayed out of the public eye since being accused of sexual misconduct by multiple women but he has denied all allegations of non-consensual behaviour.