It’s the surgery that dare not speak its name as macho Hollywood stars go under the knife.

While some are open up to Botox-ing, nips and tucks or are just too obvious to look away like Mickey Rourke, The Hollywood Reporter has exploded the secret world of macho a-listers who get cut in an effort to look good.

 "It's much more pussifying for a male actor to be seen in before and after pictures," a major producer told THR. "They're allowed to be vain, but not act vain. It takes away from a tough-guy image."

A major casting director divulged, "I definitely see a proliferation in men having face-lifts. Like Nicholson and Pacino, they want to keep working and can't look much older than female counterparts."

But instead of full on face-lifts, these masters of machismo are using Sculptura, a collagen-based filler, similar to Botox but with far less maintenance.

While stars like George Clooney and John Travolta deny having had plastic surgery, Simon Cowell, 53, is quick to admit it.

"Botox is no more unusual than toothpaste," Cowell famously said — prompting Ryan Seacrest to quip, "Simon Cowell's had so much Botox, he can't scowl!"

Dermatologist Dr. Stuart Kaplan told THR, "Today, a man over 50 wants to stay looking 45.

"No guy wants to look 'done' or like he's trying to look 30. The end result has to be rugged, masculine, healthy. A common cry among male patients is, ‘Don't make me look like I did anything’."

And docs will charge these aging he-men around $20,000 to stay “young”.