The Vanderpump Rules cast are a very close group. Maybe too close.

During a Season 7 After Show, Katie Maloney-Schwartz revealed she slept with Kristen Doute's boyfriend Brian Carter years before they started dating.

'This was a billion years ago,' said Katie, 32. 'This was like two years before I met Tom,' referring to her current husband and co-star Tom Scwartz.

The tea: During a Season 7 After Show, Katie Maloney-Schwartz revealed she slept with Kristen Doute's boyfriend Brian Carter years before they started dating

The tea was spilled as Katie, Brittany Cartwright and Lisa Vanderpump sat for the After Show and a producer asked offscreen: 'Can you tell me the first time you met Carter?'

Brittany interjected with a laugh: 'Uh oh, does Lisa know about this?'

'What's coming, I just feel like this is not gonna be a normal situation,' Lisa joked.

'In 2008... I was at a club with some friends, it was a birthday... and I met Carter...,' Katie paused as Brittany giggled.

Forever ago: 'This was a billion years ago,' said Katie, 32. 'This was like two years before I met Tom,' referring to her current husband and co-star Tom Scwartz; (Brian Carter and Kristen Doute pictured in September 2018)

Ladies who lunch: The tea was spilled as Katie, Brittany Cartwright and Lisa Vanderpump sat for the After Show and a producer asked offscreen: 'Can you tell me the first time you met Carter?'

'Whaaaaaat,' Lisa said looking incredulous. 'You slept with Carter? Since you've been married?'

'NOOOOO,' both girls clamored. 'This was a billion years ago,' said Katie. 'This was like two years before I met Tom.'

'Oh thank god for that, I nearly went into cardiac arrest,' exhaled Lisa.

Surprised: 'What's coming, I just feel like this is not gonna be a normal situation,' Lisa joked

N obig deal: 'In 2008... I was at a club with some friends, it was a birthday... and I met Carter...,' Katie paused as Brittany giggled

'Everyone has their ho days back then... Lisa I'm sure you did too...' chimed in Brittany.

'Ho days? Well, of course before I was married. Yes, but I didn't meet somebody, sleep with them, get drunk, and never see them again,' Lisa replied.

Katie leaned in: 'Carter was like... literally... one of only my one-night stands.'

Ho days: 'Everyone has their ho days back then... Lisa I'm sure you did too...' chimed in Brittany

Too much info:'Ho days? Well, of course before I was married. Yes, but I didn't meet somebody, sleep with them, get drunk, and never see them again,' Lisa replied

The producer then asked Tom when he knew of the quick affair and Tom admitted he knew before Kristen and Carter started dating.

Katie admitted she told Tom about it one night when they all ran into each other at a bar. Tom didn't mind.

When the producer's approached Kristen and Stassi Schroeder about the subject, the ladies admitted they had a discussion about it as well.

Truth time: The producer then asked Tom when he knew of the quick affair and Tom admitted he knew before Kristen and Carter started dating

Keen eye: Stassi recognized Carter as Kristen was scrolling through Bumble and exclaimed: 'Oh... Katie slept with that guy like eight years ago!'

Stassi recognized Carter as Kristen was scrolling through Bumble and exclaimed: 'Oh... Katie slept with that guy like eight years ago!'

Kristen had reservations at first but then said: 'Stassi was like "dude, she banged him once, no big deal'"

When asked what happened the first time they all hung out, Kristen replied: 'Yea... Katie was like "Of alllll the guys in LA" ... then she looked at Carter and was like "yea I don't even remember it." She was like totally dismissive.'

Stassi said: 'It was just a one-night stand. A wasted one-night stand.'

Kristen ended the interview with a shrug: 'It's L.A.'