Grant Kemp just gave a whole lot of NSFW details on Ali's supposed cheating.

Bachelor in Paradise star Grant Kemp has elaborated on his claims on Monday that ex-girlfriend, and Australia’s Bachelorette, Ali Oetjen cheated on him when they tried to make their relationship work in Los Angeles.

In an interview with Kyle and Jackie O on Tuesday morning, Kemp spared few details regarding what actually led to the breakdown of their relationship.

Three days into her time over there, he told the show, they went out partying. When they came back home with a group of friends, he went outside, only to come back in five minutes later to find her with another man.

“So the stairs are inside my house and I walked back in with my friend Sabrina, who witnessed this whole thing. We just saw this guy going down on [Ali] on the stairs so I kicked her out that night.

“This guy was my friend and she was the one who wanted to have a threesome and she told him that. So I took her to the other room and asked if that was true. She said no and [later on], I walked back into that. That’s what happened.

“There were people literally on the couch and I walked in with my friends and she didn’t know,” he said.

Grant said at the time he was “shocked” and “didn’t know what to think”.

“She went upstairs and I said, ‘You need to get all of your stuff in your suitcase now and leave’. She went to a hotel, and left the next night. She was blowing up my phone, and I said, I am about to block you and I did.

“She was like, ‘Please please I hate myself please, I am so sorry I can’t believe I did that’.

“That was the last time I spoke to her.”

Grant said he wanted to come out publicly about what actually happened between the two to clear his own name.

“The only reason I wanted to talk to you guys was because I was being attacked because of the articles that came out saying I wanted to have a threesome with her and she ran home scared. That’s not what happened, at all. It’s the opposite of that.”

We recap the Bachelor in Paradise finale: