Gerard Butler Gerard Butler

Gerard Butler made not one, but two rookie mistakes recently. The first was to trust that Brandi Glanville can keep a secret. The second was having no idea who Brandi Glanville was!

After The Real Housewives of Beverly Hills star revealed last year that she had slept with Butler, Glanville was publicly shamed after the actor said later that he didn't even know who she was.

Photos: Shocking celeb couples

On Monday, Butler finally set the record straight during an interview with Howard Stern. "Here's the thing. You're at a beach party, you're having fun and this girl comes along," Butler explained. "'So, what do you do?' She says, 'Doesn't matter.' We hung out. We had a little bit of fun. ... It was a one-afternooner, but it was fun. She is wild."Little did Butler know the drama that "one-afternooner" would cause. "I'm walking down the street and this pap ... says 'Brandi Glanville says you're great in bed!'" Butler continued. "And you know what I said? 'Who's Brandi Glanville?' 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---ing tell people about it!"

Photos: Give these stars a show!

Once he figured out his mistake, Butler said he reached out to Glanville to apologize. "I called and said one, 'I'm not very happy you did that because there are certain things you gotta keep a little private.' And two, 'I'm sorry because I said I didn't know who you were!'"Glanville appeared on Watch What Happens Live Monday night, where she issued an apology of her own. When host Andy Cohen asked if she felt "vindicated" by Butler finally acknowledging their hookup, Glanville responded: "We had a little texting today, and I think he's a doll and I feel bad for what I said. He is lovely and I appreciate him making it right."