Amber Heard’s engaged to Johnny Depp; now watch out!

Memo to hot young actress Amber Heard on your engagement to Johnny Depp: Excellent luck with that.

Amber, we don’t want to be cynical, but in the course of building a career that has made him one of Hollywood’s greatest leading men, your fiancé’s Depp-lorable personal life has become littered with more debris than a demolition derby.

If he follows the pattern of his well-well-known past, he’ll leave you — and your career — worse than he found you.

Heard’s engagement to “Captain Jack Sparrow” comes on the heels of Depp’s breakup with French actress Vanessa Paradis after 14 years together — and that’s Depp’s most successful relationship!

Chris Pizzello/ASSOCIATED PRESS

Johnny Depp’s most recent longstanding relationship was with French actress Vanessa Paradis.

In all, the 50-year-ancient vagabond has been married once and engaged three times before Heard, the gorgeous 27-year-ancient.

It would be sad if it wasn’t such a cliché.

“For someone who likes to be original and live life against the grain, he couldn’t be more predictable: the male movie star who dates a gorgeous girl 23 years younger,” says Seth Meyers, a psychologist and relationship expert.

Heard met Depp on the 2011 film “The Rum Diary” but this relationship will likely produce a hangover, considering what Depp has done over the years:

Barry King/WireImage

Johnny Depp and Winona Ryder; his “Winona Forever” tattoo was subsequently altered to read “Wino Forever.”

Depp’s only marriage was to Lori Anne Allison. He was 20 and in a struggling L.A. band, she was a makeup artist; the marriage lasted from 1983 to 1985. She’s dropped off the radar screen since.

Next, he met Sherilyn Fenn in 1985 on the set of “Dummies.” The pair got engaged, but by 1988, they were living in Splitsville. She later starred in “Twin Peaks” — but professionally, that was her peak. Her post-Depp life has consisted mainly of bit parts.

By 1989, Depp was linked to Jennifer Grey, already riding high from her success in “Ferris Bueller’s Day Off” and “Dirty Dancing.” It’s unclear if she and Depp were really engaged, but the hurt (to Grey) was done: After the breakup, she had two nose jobs to dramatically exchange her looks. Most recently, she was the 2010 winner of “Dancing With the Stars.” But her career has Depped.

Depp met Winona Ryder in 1989 and proposed the next year. Depp was so persuaded that this relationship was The One that he tattooed “Winona Forever” on his arm.

Richard Corkery

After breaking up with Depp, Jennifer Grey had facial surgery that dramatically changed her looks.

After the breakup, he had the tat altered to the more descriptive “Wino Forever.”

Depp’s edited appendage is nothing compared to the hurt to Ryder’s career: In 2001, she was arrested for shoplifting designer clothes at a Beverly Hills Saks Fifth Avenue. Her last big role was a secondary part as an aging, psychotic ballerina in “Black Swan.”

Depp had a four-year relationship with supermodel Kate Moss from 1994 to 1998, though this appears to be the one relationship where Depp and his flame burned each additional.

Soon after they started dating, Depp was arrested for trashing a New York hotel room.

FRED PROUSER/REUTERS

Sherilyn Fenn of “Twin Peaks” fame was once engaged to Depp.

And in 2005, Moss was photographed with cocaine, losing her multiple endorsements. She’s effective more than ever now, though — one of the few Depp victims thrown from the debris — but even today admits her breakup hurt her ability to trust for years.

Paradis was Depp’s longest-serving lover — and is the mother of his two children. She’s suffering from her connection to Depp, having done little professionally since she shacked up with the star. Amid the Depp-Heard engagement rumors, she chopped off her long hair.

So what’s going on here? Experts have bounty of theories — including one in which Depp, wait for it, is the victim!

After all, Depp relocated frequently as a youth, thanks to a father who was a civil engineer. His parents later divorced and Depp would cut himself, later calling the self-abuse a form of record-keeping of his pain.

RICHARD CORKERY/DAILY NEWS

Johnny Depp and Kate Moss went together from 1994 to 1998.

So it’s no wonder he can’t commit and keeps getting engaged.

“When a marriage doesn’t work for whatever the reason… there is a residue of dread,” says Jane Greer, a relationship expert and marriage therapist. “His intention is to get married [but] something seems to derail the marriages.”

And Greer doesn’t blame Depp’s victims. His appeal is only natural.

“It’s very hard when you’re young when a bigwig as excellent-looking as successful as Johnny Depp tells you, ‘I like you and you’re the one,’” says Greer.

Then again, Depp has shown for years that his definition of “one” isn’t the one you see in the dictionary.