Extra-moist bathroom wipes — championed by celebrities like Terrance Howard and will.i.am — have become a catastrophic pain the the a$# in sewer systems around the world.

The increasingly popular rear-end cleaners look like baby wipes and are supposed to be flushable.

But public-works employes from Denver to London say the towelettes are nuisance because they don’t degrade after use and cause huge sewer clogs that cost millions to clean up.

The most dramatic example of the problem came in London, where workers this summer found a colossal ball of wipes and coagulated fat blocking a sewer main. The 15-ton, bus-size clog took three weeks to dislodge.

The wipes also caused a wave of clogged pipes and broken pumps all over the Washington, DC, area. Officials in the DC suburbs have spent a fortune installing shredders to break down the little cloth towels, which don’t break down like real bathroom tissue.

One town in Western New York got so overwhelmed, officials installed pipe strainers to help them track which households used wipes — and then went door-to-door pleading with residents to stop flushing them.

Complaints about the wipes harming sewer systems started some four years ago, about the time that the “flushable”-wipes market started to take off, The Associated Press reported.

Now the butt-wipes game is a $6 billion business that has been injected with a big dose of celebrity glamour.

Stars have talked up wipe use in interviews, agreeing that women who don’t moist-wipe their backsides are “unclean.” A brand called One Wipe Charlies is even endorsed by several NFL centers.

The wipes are heavily marketed toward men. One product called Dude Wipes encourages guys to “kill the swass monster” below a cartoon image of a pair of filthy anthropomorphic jeans.

A spokesman for Dude Wipes said the company’s towelettes are “not the problem” — and CEO Sean Riley said, “They are certified disposable . . . Unfortunately, a whole lot of things are going into septic systems.”

One Wipe Charlies did not respond to a request for comment.