Why is Matt Bomer singing? Why is Channing Tatum pumping? All is revealed ...

Matt Bomer not only strips in “Magic Mike XXL,� he sings — and it’s all thanks to Channing Tatum and Joe Manganiello.

Seems that in between takes on the first male-stripper film, which had a much smaller budget than the sequel opening July 1, Bomer and the gang would entertain the extras.

“Channing would shove a microphone in your face and say, ‘Do something,’ � the “White Collar� star told “Late Night� host Seth Meyers on Tuesday. “And Joe Manganiello — who I went to college with at Carnegie Mellon — knew that I sang and said, ‘You should sing a song.’ So I did, and Channing remembered that, and he was like, ‘You’re singing in this one.’ �

The actor, whose character serenades one of the ladies he’s entertaining in the sexy sequel with Bryan Adams’ “Heaven,� said he wasn’t totally up for the task.

“I was like, ‘Oh man,’ because, you know, it’s daunting to have to take your clothes off in front of strangers and then to sing live on top of that.�

Meyers said he’d rather strip than sing, but Bomer explained that there’s something about disrobing that makes singing easier. (Yes, he really did!)

He also recalled his college days with “True Blood� alum Manganiello.

“We did animal projects together. ... I became a heroin addict who worked at a tanning salon, but also, I was a peacock. We’ve done clown work together, we’ve done Shakespeare together and now we’ve stripped together,� he said. “I don’t know where to go from here! What is the next logical step?�

So many answers to that question ...

Meanwhile, thanks to a tired-looking Tatum’s continuing effort in the nonstop promotional blitz for “XXL,� viewers of “The Tonight Show� learned that Magic Mike is simply “like regular Mike, except magic.�

That according to 8-year-old Steven from Dallas, who was among the kids who were asked to write scenes for the movie based on its title alone.

Not-so-spoiler alert: The flick is about exotic dancers who head off to a strippers convention.

Not-so-surprising alert: That notion did not occur to the young writers.

Tatum, on whose life the original 2012 film was loosely based, read the kids’ scenes with host Jimmy Fallon and started cracking up before any actual reading commenced. He then assumed the role of Magic Mike, who is “like regular Mike, except magic.�

The first and perhaps funniest of three bits featured a suggestive-sounding Mike fixing a friend’s bike tire by “pumping it� — a lot — while melodramatic music played.

In 6-year-old Asher’s scene, Mike was charged with “keeping aliens out of the lovely planet,� only to reveal that the reason he was doing a lousy job was because he was actually the king of the aliens.

The final scene came from Sadie in Virginia. Fallon switched things up and played Magic Mike, with Tatum taking on the role of a sad “Magic Bird� who needs Mike’s help to feel better.

The sexual tension: tangible. The bonus: singing.

“Magic Mike 3� producers, you know where to find that next script ...

Follow me on Twitter @NardineSaad.