Justin Timberlake Is Off The Market As He Celebrates Bachelor Party In Las Vegas

He was one of the most eligible single men in Hollywood but now that Justin Timberlake is putting a ring on Jessica Biel- he's going out in style and partied up a storm in Las Vegas on Thursday night for his Bachelor Party.

The Sexy Back star was with a 25-deep entourage of friends as they hit up Surrender Nightclub at Encore Las Vegas.

It was apparently a "Rat Pack" theme with the boys decked out in retro suits and they dined at Sinatra Restaurant in Wynn before going to the club just before midnight.

Sources tell okmagazine.com that JT and his crew partied inside a private bungalow overlooking the palm-tree lined pool.

"Justin was all smiles but stayed hidden inside the private enclave," the insider said.

"He was sipping on 901 Tequila throughout the evening but his posse were seen enjoying vodka and Red Bull shots all night."

Justin proposed to his long-term love late last year and are busy planning their nuptials - the details of which have been kept very hush hush.

As they say.. what happens in Vegas stays in Vegas so JT was careful not to have any photos taken of him!