"We hung out, we had fun, and then I never saw her again," the actor says on "Watch What Happens Live."
During Brandi's January 2017 appearance, she said she and Gerard "had a little week of fun" and gave the actor an "11" out of 10 when asked to rate his skills in bed.
"I had no idea who she was," Gerard told Andy Wednesday. "I kept saying, 'What are you doing,' and she said, 'Doesn't matter, not important.'"
"When you met her, you didn't know that she was on TV or anything like that?" Andy asked.
"No idea," he said. "It was kind of a crazy time. Anyway, we hung out, we had fun, and then I never saw her again. And then suddenly, I was walking down the street with a director, and these guys from TMZ come running down the street going, 'Hey, what about you and Brandi Glanville?' And I'm like, 'Who's Brandi Glanville?' Because I didn't even know her last name! So I'm like, 'Who's Brandi Glanville?' She got pretty upset."
You can compare and contrast his story with the actual TMZ video. It's pretty accurate.
50 Cent, who was sitting beside Gerard on "WWHL," told his "Den of Thieves" co-star that "that don't count."
"If you don't know her last name, that didn't happen," 50 Cent joked.
"Then I'm a virgin!" Gerard said laughing.
Brandi didn't find the comment as funny because she immediately took to Twitter following the interview to urge her fans to listen to Gerard's March 2017 interview with Howard Stern if they "want to know the truth."
So TooFab went ahead and dug up those receipts.
When Butler stopped by Stern's Sirius XM show, he said -- ready for it? -- the same thing he said Wednesday night, almost verbatim, leading us to believe the actor may have one of the best memories in Hollywood.
"It was a one-afternooner, but it was fun," Butler told Stern. "She is wild."
Gerard recalled the same event with Stern that he did with Cohen, saying he was once approached by paparazzi who said to him, "Brandi Glanville says you're great in bed."
"And you know what I said? 'Who's Brandi Glanville?'" Butler told Stern. "Because one, I didn't know her last name, and two, I didn't know she was a celebrity, and I didn't know she was going to f-cking tell people about it."
"Here's the thing," he continued, "you're at a beach party, you're having fun, and this girl comes along. 'So, what do you do?' She says, 'Doesn't matter.' We hung out. We had a little bit of fun."
Butler told Stern he called Brandi up once he heard she was talking publicly about their fling.
"I said, one, 'I'm not very happy you did that because there are certain things you keep a little private.' And two, 'I'm sorry I said I didn't know who you were!'"