Bet he regrets this one!

By now, we've all seen the video Brazilian bombshell Tatiana Neves filmed of Justin Bieber asleep after a wild night of partying in South America, and now the curvy bodybuilder is spilling all the juicy details of her fling with the Canadian pop star!

Neves spoke to Globo TV's Fantastico about what went down between her and the "Boyfriend" singer, but stopped short of confirming whether the two had sex when asked by the interviewer.

"What do you think, if I was sleeping in the bedroom, just me and him?" she replied.

The brunette beauty claims she was invited to the house party by a DJ pal, but when asked if she knows anything about the other girls at the soiree, she confessed she doesn't because she spent the entire night behind closed doors with The Biebs!

"No. I'd already gone into the bedroom with him," she teased.

So how did she manage to take footage of the Hollywood heartthrob?

"I was sleeping, and woke up, he was sleeping and I was speaking with a girlfriend," she added.

Better be careful who you bring to bed next time, JB!