RHA / ZOB / WENN 1 / 18
RHA / ZOB / WENN 1 / 18

LOS ANGELES (AP) -- Arnold Schwarzenegger is confirming that he had a "hot affair" with actress Brigitte Nielsen at a time he and Maria Shriver were dating and already living together.

RELATED: Notorious Cheating Scandals

Schwarzenegger and Nielsen co-starred in the 1985 film "Red Sonja." Nielsen wrote in a memoir published last year that she and Schwarzenegger had an "outrageous affair" while making the movie and that she did not know until later that he was involved with Shriver.

RELATED: Aging Action Stars: Hot or Not

In his memoir "Total Recall," coming out Monday, Schwarzenegger writes that he and Nielsen did indeed have a "hot affair," but he knew it wouldn't last. In fact, their "fling" only made him realize that he wanted to marry Shriver.

RELATED: Hookup Rumor du Jour: Schwarzenegger Swaps Spit With Dewy Brunette

Nielsen would soon marry Schwarzenegger's fellow action star, Sylvester Stallone.