Heeeeere's Johnny? More like here's Jack Nicholson—and Jack Quaid.

After all, Dennis Quaid revealed that his and Meg Ryan's 31-year-old son was named the legendary actor. That is, with a little help from his older brother Randy Quaid.

"I just got to L.A. and my brother got a part in a movie called Missouri Breaks," Dennis told E! News' Francesca Amiker in an exclusive interview. "So I drove my brother's car up to Montana. My very first movie set, I'm watching these actors, my real heroes. We hung out at Jack Nicholson's house every night. He and Randy were good friends."

They gave me a lot of encouragement," the Parent Trap alum continued. "And that's a true story that we named him Jack after that."

So it's no surprise Jack followed in his namesake's footsteps.

"Nobody pushed him into being an actor," Dennis said. "He was 4 years old and he's carrying around a video camera making little movies and he's still doing that."

And the Boys star did it on his own.

"He was in the drama department in high school and didn't want him to be a child actor with all that pressure that went with it," the 70-year-old continued. "Got his own agent. The next thing I know, his first movie is Hunger Games. And the second thing he's doing, he's working with Martin Scorsese."

As for Dennis, he's working on The Long Game, which hits theaters April 12.

"It's so uplifting," he said about the film, based on a true story about the 1957 Texas state high school golf championship. "It reminds us of who we used to be as a country and how far we've come, and where we still need to go."

Now, you need to go and learn more about your favorite stars' real names...

Cardi B took on the name Bacardi after family and friends started calling her sister Hennessy. Later on she shortened the name to something that suited her quite a bit more.

Before she became the Duchess of Sussex, Meghan Markle was briefly known as Rachel. 

Shania Twain shared the origin story of her stage name during an appearance on Apple Music's Home Now Radio: "In short, I was born, Eilleen Regina Edwards, and then I was adopted and I became Eilleen Regina Twain. Then I became a professional singer and I needed a stage name that sounded a little less like my grandmother's name, because I'm named after my grandmother, both my grandmothers, Eilleen and Regina. I think, in my mind, I was just not really wanting to be called my grandmother's name onstage, so I decided to change it to Shania Twain. I met somebody with the name Shania, thought it was beautiful, and Shania Twain was born."

Oddly enough, Gigi Hadid got her stage name in school when the teacher would confuse her and a girl named Helena. Since her mom called her "gigi" as a term of endearment at home, she told the teacher to just call her Gigi and it simply stuck. 

If you're looking for an explosive action-star name, how about Vin Diesel instead?

Miley Cyrus' bright smile is what inspired her childhood nickname, Smiley. Eventually the name was shortened to Miley and it stuck. 

Apparently the singer looked more like a Bruno than a Peter, so one day his dad started calling him Bruno. Ever since, he has been known as Bruno Mars.

Before the meat dresses and chart-topping music, Lady Gaga was just an everyday girl from New York.

Jason Sudeikis confirmed on Today that he was named Daniel after his father, but following some confusion, his mom started using his middle name Jason to avoid confusion. 

Emma Stone ended adopting this stage name after finding out that the Screen Actors Guild already had a member registered under her birthname. 

Turns out Reese isn't even Reese Witherspoon's middle name. The actress chose the moniker in honor of her mother, whose maiden name is Reese.

Every artist has an alter ego, and Lana Del Rey just happens to be the persona of choice for the singer. 

In 2014, Frank Ocean legally changed his name because, why not? 

A little known fact about 30 Rock's Tina Fey is that she is actually named Elizabeth. The comedian made a not so subtle tribute to her birth name by naming her character Liz Lemon.

This pioneer of West Coast rap would later go on to be known as Snoop Dogg.

Turns out the "Royals" singer is really into learning about the aristocracy, hence the reason why she chose the name Lorde, but with a feminine 'e.'

Before he started shaking his bonbon for the masses, music superstar Ricky Martin went by this everyday name.

It's hard to believe that Iggy Azalea was born Amethyst Kelly!

Fans were confused when Taylor Swift thanked then-boyfriend Adam in an acceptance speech, which lead people to the discovery that Calvin Harris is simply a stage name. The DJ told Shortlist magazine he chose the name because his first single was more soulful and wanted something a bit more "racially ambiguous."

Before she became a household name, this was what erstwhile Friend Jennifer Aniston answered to.

Alicia Keys didn't always have such a musical name.

Before he became arguably the biggest movie star in the world, Tom Cruise went by this name.

Back when she was born in 1980, this was how the future bigtime actress Natalie Portman greeted the world.

Before she became a big-time TV star and married Ellen DeGeneres, this was the name Portia de Rossi answered to.

Guess music superstar Elton John didn't think his original name would be a hit with audiences.

Check former Paris Hilton BFF Nicole Richie's birth certificate and this is the name you'll see.

All it took was a nickname from some high school friends, and U2 frontman Bono's famous moniker was born.

We agree. Carmen Electra is much more effective when it comes to selling a sexy Baywatch persona.

True, Jamie Foxx just seems more fitting for an Oscar-winning Hollywood party guy.

Before she'd starred in dozens of huge Hollywood movies and married two Tinseltown A-listers, this was the name Demi Moore went by.