Arnold Schwarzenegger had an affair with Brigitte Nielsen shortly before she wed Sylvester Stallone. The philandering actor has revealed he had a steamy fling with the actress - who was once married to his good pal Sylvester - during the early years of his relationship with now ex-wife Maria Shriver.

Arnold has confessed to having an affair with the Danish actress while he was dating Maria in his new autobiography, according to TMZ. He wrote that he and Brigitte became close while filming Red Sonja together in 1985; the same year she married Sylvester.

The Terminator film star's admission comes more than a year after Brigitte originally blew the whistle on their "outrageous affair" in her own memoir You Only Get One Life, in which she claimed she didn't know he was living with Maria at the time.

Maria is said to be furious with the actor for doing an interview about her reaction to his new book on 60 Minutes because she did not receive an advance copy of his tell-all and was not contacted by the show to give her own reaction before their interview. He has also reportedly told Maria that she should not expect a share of the profits from his autobiography, Total Recall: My Unbelievably True Life Story, even though much of the book is about their relationship.

Arnold recently admitted his affair with his maid was the "stupidest thing" he ever did in his marriage: "I think it was the stupidest thing I've done in the whole relationship. It was terrible. I inflicted tremendous pain on Maria and unbelievable pain on the kids."