Reformed party boy BRUCE WILLIS plugs a premium brand of vodka – despite lifelong battle with booze!

While substance abuse experts are outraged, sources say The Expendables tough guy is shrugging off the controversy.

"Bruce is honest about his alcohol demons, but at the end of the day he’s still a businessman," an insider told The ENQUIRER.

"He has no problem hawking vodka if the price is right. He says, ‘Money is money, and this is business.’"

Willis’ logic, however, is twisted, according to addiction expert Dr. Gregory Smith, M.D., of Redondo Beach, Calif.

"Since Bruce Willis has had a problem with alcohol, this is hypocritical," Dr. Smith told The ENQUIRER.

"He’s sending the wrong message by lending his celebrity to a product he’s clearly renounced in the past."

The one-time Alcoholics Anonymous member – who was busted for marijuana possession during his college years – has even confessed: "Booze nearly wrecked my career."

But raising three daughters with ex-wife Demi MooreRumer, 22, Scout, 19, and 16-year-old Tallulah Belle – and his second marriage to model Emma Heming has changed the star’s take on life, said the source.

"Marriage, fatherhood and age definitely tamed Bruce," said the source. "He’s extremely strict with his daughters and constantly lectures them on the dangers of excessive drinking."

Despite that, visions of greenbacks apparently prompted Willis to plug Poland’s Sobieski Vodka, said the source.

"Because Bruce is so famous and endorses the brand, people are going to buy it," said the source.

"It must have been a big paycheck, and I hope it’s worth trading in his principles to promote drinking."