Justin Bieber And Sean Kingston's NYC Boys' Night Out Sounds Expensively Epic

Justin Bieber may be enjoying the simple pleasures of four-wheeling in Canada while he visits his father who has just had surgery, but according to reports the teen got his pop star mojo on in a serious way on Monday night.

The 19-year-old turned heads at the weekend during New York Fashion Week when he debuted his heyday fringe and a now-culled gossamer mustache.

Spotted sitting front row as he made fashion rounds on Sunday, Justin capped the night with a trip to 1 Oak nightclub accompanied by friends.

But, it was on Monday night that Bieber reportedly partied up an expensive storm and then some courtesy of longtime buddy, Sean Kingston.

The superstar and his all-male coterie hit NYC's Serafina restaurant on Monday for a late supper with a crowd gathering on arrival and exit.

"He arrived around 11 p.m. with four friends and about five bodyguards," a diner told E! News.

The website then describes a Rat Pack like scenario during which Justin and his crew were swept to a private room inside, before servers brought a stream of pasta dishes.

Mayhem ensued as the boys left the eatery reportedly around 12.30 pm. Around 30 fans swarmed the "Baby" singer.

But, to his credit, Bieber stuck around and gave the clamoring ones some face time.

"He rolled down the window and started signing autographs and talking to fans," a fellow diner told E! News. "It was so nice of him and the girls were just going crazy, screaming and crying. Even one of the mothers who was there with her daughter couldn't get over it. We heard her say, 'My God, this is a miracle, we waited six hours for this'."

From there, the party headed to the Meatpacking District's Griffin nightclub.

According to New York Daily News' Confidenti@l, the teen singer, Kingston, and a "massive crew of dudes" --- which surely includes security too as E! News reports there were four male guests in Justin's party --- the group took over the center of the room.

"They bought three tables in the middle of the room and ordered $5,000 worth of alcohol. They had Patron and Bieber was chugging out of the bottle," a source told Confidenti@l.

Apparently the female contingent in the club was desperate to get close to the star. But, alas, his beefy security reportedly fended them off.

Later, the illustrated teen reportedly "let" a couple of girls join him and his crew at their alcohol-laden table.

It's claimed Justin and Sean got into a friendly faux-row trying to decide who would pay for their big night.

Reportedly, Canada's finest tried several times to get his plastic out, but in the end Kingston settled up.

The boys' night out reportedly came to a halt around 3:45 am.

After an eventful year with plenty of allegations and accusations still to be determined and a possibly sizable helping of fiction added to that mix --- apart from a recent run-in with a clubgoer in a Toronto nightclub and the fuss over Bieber's now-departed mustache --- these are relatively quite times for the singer.

With some of the focus switching to Justin's upcoming new music and movie-documentary Believe, which recently screened at the Toronto International Film Festival, at times Justin appears to be in a more reflective frame of mind.

After attending a Sunday morning church service during his NYC visit, the singer was remarkably frank in a tweeted message to the Pastor afterwards.