Backstreet Boys

Brian went on Bob 93.3 in North Carolina this morning, telling the host, "I'm proud that he would go into this situation willingly ... Last time it was a lot worse. He really went into rehab unwillingly the last time."

TMZ has learned A.J. -- who's struggled with abuse for years -- was so hammered and rowdy on a BB fan cruise last month, that several passengers lodged complaints ... with some even demanding a refund.

One cruise staffer tells us A.J. and his crew acted like "drunken fools" for the entire five-day trip.

But after the cruise, the abuse continued ... and more people in his life threatened to jump ship.

Sources close to the singer tell us A.J. became so difficult to work with during rehearsals for the upcoming BB tour that multiple people were "ready to quit."

One source tells TMZ McLean has been "out of control" in the last few months because of substance abuse, and it was interfering with plans for the Backstreet Boys' upcoming tour with New Kids on the Block.

Sources say on a Backstreet Boys cruise last month ... A.J. appeared under the influence much of the time.

McLean has battled addiction for years. He was in rehab in both 2001 and 2002 for alcohol and cocaine abuse.

McLean made a cryptic reference on his Twitter account, writing on January 9, "I love u all and wish me luck! I start my sober journey tomm!"

On January 10, McLean tweeted, "See u on the other side!"

Video shot during a BSB cruise for fans last month shows McLean with what looks like a beer -- amber liquid with foam on top.

It was all for a session with photographer Tyler Shields -- the guy who shot those semi-naked Lindsay Lohan "Inferno" pics.

AJ has been battling his issues with alcohol for years -- and we're guessing this whole thing was some sort of artistic interpretation of his inner struggle.

Question is ...

Sources tell TMZ .... the "Jersey Shore" star is close to a deal -- but he's not the only act that's being considered. We're told Boys II Men is also in the running.

BSB's rep tells TMZ, A.J. -- who was recently diagnosed with the leaky eye infection -- is "doing fine" ... and the band's current tour will go on as scheduled.

As for the other guys -- we're told the rest of the band was inspected by a doctor as soon as they discovered A.J.'s pus problem ... and they all tested negative.

It all went down inside the Hard Rock Hotel Friday night -- AJ and his then girlfriend Rochelle Karidis were partying inside the Wasted Space nightclub, when he sprinted to the jewelry store inside the casino, picked out a ring, and ran back into club.

But alas, clear as day in the rider for the Backstreet Boys' current tour, is the demand for 24 bottles of beer and two bottles of "high quality Italian or French red wine." A votre sante!

The chick, Wendy Rice, is the one confronting him in the video posted earlier today -- she tells us during their argument McLean repeatedly told her "I'm an alcoholic."

As McLean nearly falls into the street, one of his friends calls him out -- right out in the middle of Hollywood -- emotionally confronting the guy who went to rehab for alcohol and cocaine abuse in 2001... and again in 2002.

Witnesses inside the Key Club say they saw McLean taking shots and drinking beers during the show. After the confrontation, McLean's friends forced him into a cab and sent him home.

TMZ talked with a Jive Records spokesperson who told us, "Reports about Jive Records dropping Backstreet Boys are completely untrue. The group is about to embark on a worldwide tour in support of their album, Unbreakable, starting Feb. 16 in Toyko, as well as some high profile television appearances."