Leal was first linked to the actor when the paparazzi spotted the two together on September 24, which was Kutcher and wife Demi Moore's sixth wedding anniversary.
The 23-year-old has now claimed that she did spend the night with Kutcher at San Diego's Hard Rock Hotel because the actor said that he was "separated" from Moore.
Leal said that it was Kutcher who made the first move, telling Us Weekly: "He just came up and kissed me."
Leal said that she, Kutcher and another woman then stripped down and got in a hot tub in the actor's hotel suite.
"I didn't think it was out of the ordinary. I wasn't self-conscious about getting naked," Leal said.
After they retreated to the bedroom, Leal said that Kutcher "lost his towel and [she] took [her] robe off", adding: "Then we had sex… He was good."
The conversation then turned to politics, according to Leal.
She explained: "I told him I was a Lutheran from Texas. He said, 'Oh my gosh! Are you a Republican?'… [He asked me about] up-and-coming candidates. I said Rick Perry. He asked if I'd vote for him. I said I didn't know and he laughed. He laughed at pretty much everything I said."
Kutcher reportedly told Leal that he enjoyed spending time with her before they parted, with Leal claiming that the star said: "I'm an actor 90% of the time [and] it's fake. It's nice to have moments that are real."
Reps for Kutcher and Moore haven't commented on Leal's interview.
Moore first raised questions about the state of her and Kutcher's marriage when she posted a series of cryptic messages on Twitter.
Kutcher has seemingly denied allegations of an affair by tweeting a link to the Public Enemy track 'Don't Believe The Hype' and later advising his fans not to "assume" anything.
The couple went camping with their Kabbalah instructor this past weekend, mere days after Moore reportedly met with a divorce lawyer.
> Ashton Kutcher, Demi Moore spotted together amid split rumours