MTO SHOCKER: Mariah Carey Gets DRUNK AND TURNT UP . . . And Acts INAPPROPRIATELY With A MAN . . . Not Her FIANCE!!!

: Mariah Carey had a wild club night in Las Vegas. She was holding a glass in hand . . . and holding with two hands onto her DJ friend as she partied the night away in her VIP DJ booth at 1OAK.

The pop diva princess was having a blast as she talked to the crowd and even got on the microphone for a bit during the set. Mariah stayed til nearly 3 a.m. as she and her DJ were talking the whole night together and posing for the cameras.

Mariah reached out her arm with a glass in it to the party goers to do a toast to the crowd at 2am.

Mariah also swayed her head around to the beats as her hair was fully in her face at some points during the late evening party.