AJ McLean Details First Time Using Cocaine Before Backstreet Boys’ Video Shoot

Backstreet Boys member AJ McLean once had a 2 AM call time -- and made a midnight decision that stuck with him for years.

The singer is reflecting on his career in the new docuseries “Boy Band Confidential: A Hollywood Demons Event,” revealing his first time trying drugs went down in 2000 ... just hours before a late-night video shoot.

At the peak of BSB fame, AJ says the night started low-key -- dinner with the guys, then a nap -- but things took a turn when he woke up groggy ahead of that brutal overnight shoot. A friend offered him something to “wake up” -- and pulled out a bag to seal the deal.

Watch the clip ... at first, AJ says he wasn’t having it -- firing off a string of “no, no, no’s” -- but the offer didn’t disappear. It lingered … sitting there within reach. Eventually, he gave in.

“I very easily could have done the video shoot without being on drugs,” McLean said. “I think in that moment, I just caved and decided what's the worst that could happen."

"Worst things happened.” Yeah ... hindsight hits a lot harder.

The revelation is one of many candid moments in the 'Bad Boy' docuseries, which digs into the pressure-packed reality behind boy band fame -- where insane schedules and nonstop demands made bad decisions a little too easy.