In the glamorous world of Hollywood celebrities, even the most A-list stars face their fears.

Stars like Jennifer Aniston and Kristen Bell got real about what scared them the most.

‘FRIENDS’ STAR JENNIFER ANISTON SETS BOUNDARIES WHEN IT COMES TO AUDITIONING: ‘I WOULD NEVER’

“Friends” star Aniston confessed being in the air or underwater terrifies her. 

While Aniston was jet-setting with “Friends” co-star Courteney Cox, she shared that her trip took a turn for the worse when she traveled by plane in 2019.

“We heard an explosion, which sounded like a pothole if it was a car big enough to go over the Grand Canyon. It was so loud,” Aniston previously said during an appearance on “Jimmy Kimmel Live!”

“I have a real fear of flying, obviously, but nobody else does. So, Courteney Cox, whose father is a pilot and is never afraid, says, ‘Should we have checked that? Is everything okay?’ They were like, No, no, it’s taxiing, it’s going smoothly.”

In 2015, Aniston admitted being underwater freaked her out.

“I basically have a real fear of going underwater,” the Hollywood actress said during a screening of her movie, “Cake,” according to E! News.

“I was a kid, and I was riding this tricycle around a swimming pool… I drove my tricycle into the swimming pool, I didn’t let go, and my brother tried to [help me],” Aniston explained. “So, I can’t go underwater and no one will believe me. I honestly can’t.”

Jennifer Aniston revealed she is also afraid of going underwater. (Michael Buckner/Variety via Getty Images)

‘BEETLEJUICE 2’ STARS WINONA RYDER, JENNA ORTEGA SHARE ‘HOLY’ BELIEF THAT FILM CAN BE ‘A RELIGIOUS EXPERIENCE’

The stars of “Beetlejuice Beetlejuice” told Fox News Digital what truly spooks them out. 

When Fox News Digital asked what their fears were, original “Beetlejuice” cast member Catherine O’Hara said she cannot stand the movie “The Exorcist.” 

Meanwhile, 22-year-old actress Jenna Ortega fears awkward social interactions. 

“I can’t go underwater and no one will believe me. I honestly can’t.”

— Jennifer Aniston

WATCH: ‘BEETLEJUICE BEETLEJUICE’ STARS SHARE THEIR FEARS

“Those social interactions where… you guys aren’t getting anywhere…” Ortega explained to Fox News Digital.

“Like a bad date?” O’Hara asked. 

“Yeah, I just hate that. I hate to bring it up. There’s this one time… there was somebody who worked for… the Four Seasons… really nice guy. But… I think I was 16 at the time, and I was having a conversation with this guy in the middle of a press…” 

“We were talking about the weather… for like 10 minutes, and we both knew, I could see it in his eyes that… neither one of us wanted to be having that conversation, because… that didn’t change our lives. So, I think those conversations are… brutal to have.”

Their co-star Justin Theroux, on the other hand, said he fears death. 

“I’m such a hypochondriac. So, of course, I fear death, which I think all of us do. Maybe that’s a natural condition,” he said.

The stars of “Beetlejuice Beetlejuice” told Fox News Digital what truly spooks them out. (Getty Images)

OLIVIA RODRIGO SUFFERS AWKWARD MOMENT AFTER UNKNOWINGLY ASKING BROTHER, SISTER TO KISS AT CONCERT

Birds appear to ruffle several celebrity feathers — including Olivia Rodrigo and Scarlett Johansson.

The former Disney star opened up about how the feathered creatures are certainly not her favorite. 

“Birds are so foreign to us — there’s not one body part that looks like ours,” Rodrigo told Rolling Stone last year.

“Everyone’s all afraid about aliens and s—. They’re like, ‘What are the aliens going to look like?’ I’m like, ‘We have birds on our planet, and we’re not scared of them. We’re fine!’” 

Former Disney star Olivia Rodrigo opened up about how feathered creatures are certainly not her favorite. (Matthew J. Lee/The Boston Globe via Getty Images)

While you’ll never catch Rodrigo watching Alfred Hitchcock’s film “The Birds,” Johansson joins the pop star in this common fear. 

During an interview with Vulture in December 2011, Johansson revealed she has a fear of birds, which made filming “We Bought a Zoo” especially difficult. One scene that featured a peacock was scary to film because she “was terrified of them” and did not want them to “get too close,” saying that “they’re like, mean.”

WATCH: ‘DWTS’ CONTESTANTS ADMIT THEIR BIGGEST FEARS

“I’m only scared of birds. Something about wings and beaks and the flapping, I’m terrified of them. That still hasn’t gone away. If they’d asked me to put a bird on my shoulder I would’ve done it, but it would’ve been hard,” she told the outlet. “Actually, my uncle is terrified of birds as well, so it runs in the family.”

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Scarlett Johansson revealed she has a fear of birds. (Paolo Blocco/FilmMagic)

Kristen Bell’s husband Dax Shepard revealed his wife loathes “pruney” fingers. 

He exposed the actress on social media, sharing a photo of her wearing gloves in a pool. 

“My bride wears gloves in the pool because she hates the feeling of pruney finger tips on skin. #Hollyweird #iloveher” he wrote on Instagram in 2018.

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The “Good Place” actress explained to fans about her fear.

“I would call it a very serious, undiagnosed and yet-to-be-discovered medical condition that tens of people in America might also suffer from,” Bell explained on “Jimmy Kimmel Live!” at the time.

“I’m not ashamed,” she remarked. “In my lifetime I want to remove the stigma of the maybe 10 people who also suffer. You are not alone!”

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Martin Freeman admitted he is strangely afraid of avocados. 

During an appearance on “The Graham Norton Show,” the English actor revealed he is hesitant to eat avocados since he is terrified of choking on the large pit or “stone” in the middle. 

“I have a fear of choking,” Freeman said. “It’s a completely rational fear — it’s happened a couple of times when I’ve eaten crisps too quickly and it’s very scary.”

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“I will confess that whenever I have an avocado, I imagine the stone lodged in my windpipe. I don’t have that much avocado!” he admitted.