Demi Moore has just revealed a shocking detail about her eight-year relationship with former husband Ashton Kutcher: threesomes.

The 56-year-old actress' memoir, "Inside Out" details how she allowed Kutcher to live out his sexual fantasy by "bringing a third person" into their bed.

Moore added that she always put Kutcher "first" and she wanted to show the 41-year-old actor how "fun" she could be. The "Ghost" star started dating Ashton in 2003 and was married in 2005 before calling it quits in 2011 and finalizing their divorce in 2013.

The actress shared how the threesomes left her with feelings of "shame." She believes that the act caused Kutcher to stray from their relationship; she said that it justified her ex-husband's cheating.

Moore also said that the people that she had threesomes with "were good, but it was still a mistake." In her book, she narrated how the sexual act "flooded her with shame," Demi believed that the "whole thing was somehow" her fault and she "couldn't shake the feeling."

Demi Moore
Demi Moore blames stress for the loss of her teeth. Pictured: Actress attends New York Premiere of Sony’s ROUGH NIGHT presented by SVEDKA Vodka at AMC Lincoln Square Theater on June 12, 2017. Getty Images/Jamie McCarthy

The actress also claimed that Kutcher cheated her a second time with a 21-year-old woman when she was filming "Another Happy Day" in 2011.

Moore detailed that Kutcher "admitted right away" when the woman claimed that she slept with the "Two and a Half Man star."

The actress wrote in her memoir that Kutcher moved out of their home shortly after the confrontation. "If I were to look back... I would say I blinded myself and I lost myself," quipped Moore.

The split caused her to abuse substances like Vicodin and alcohol and her three daughters stopped talking to her. Her former husband and friend Bruce Willis also distanced himself from the actress.

Her pain and isolation took to the worse in 2012 when she was rushed at the hospital for smoking synthetic marijuana and inhaling nitrous oxide at a party. At that time, she claimed that she only weighed 102 lbs.