Celebrity stardom has a dark side.

Many celebrities, including Britney Spears, Justin Bieber and Sandra Bullock, have dealt with stalkers. Sadly, this is nothing new. Law enforcement has been working to make life safer for stars since the murder of Rebecca Schaeffer in 1989.

The "My Sister Sam" star lost her life at the age of 21 when a 19-year-old who had been stalking her showed up at her doorstep and shot her. Robert John Bardo was later convicted of capital murder and sentenced to life in prison without the possibility of parole.

Schaeffer's death led California to create the nation's first investigative team focused solely on stalking.

Rebecca Schaeffer in a comedy series

Rebecca Schaeffer died after being shot in the chest by a stalker who showed up at her door. (CBS Photo Archive)

The state would go on to pass the Driver’s Privacy Protection Act in 1994, which prohibits the Department of Motor Vehicles from releasing people's private addresses.

But despite the changes, many stars are still being targeted.

KENDALL JENNER SEEKS RESTRAINING ORDER FROM ALLEGED STALKER WHO WAS RELEASED AFTER ARREST

Britney Spears

Britney Spears' ex husband Jason Alexander attempted to crash her wedding

Britney Spears' ex-husband Jason Alexander ended up in jail after he attempted to crash her wedding to Sam Asghari. (Getty Images)

Britney Spears' ex-husband Jason Alexander landed in jail after he attempted to crash the pop star's wedding in early June. Alexander arrived at Spears' home hours before the ceremony was set to take place. He livestreamed as he entered the property and walked around.

Security asked him to leave, and a physical altercation ensued.

Spears and Alexander married on Jan. 3, 2004, but the marriage lasted just 55 hours before it was annulled. Spears and Alexander were 22 years old at the time.

His next court appearance is scheduled for July 12.

Ariana Grande

Ariana Grande at the Grammys

Ariana Grande's stalker violated his restraining order and allegedly broke into the pop star's home on her 29th birthday. (Amy Sussman)

Ariana Grande got an unwanted birthday surprise from her stalker last month. He violated a restraining order brought against him by the pop star and broke into her Montecito home on her 29th birthday, according to TMZ.

Grande was not home at the time of the break-in, but authorities arrested him. He was reportedly charged with stalking, burglary, damaging power lines, violation of a court order and obstruction.

The man was previously arrested in September after he showed up to her home with a knife.

"I'll f---ing kill you and her!" he reportedly threatened at the time.

Justin Bieber

Justin Bieber performs

Two men once plotted to castrate and murder Justin Bieber. (Jason Merritt)

Justin Bieber has had multiple stalkers, including a New Mexico man and his nephew who plotted to murder and castrate the pop singer in 2013.

The plan began after a man in prison attempted to contact Bieber with no response. He then recruited his nephew and another man to drive to the "Love Yourself" singer's home and castrate him with garden shears before murdering him, according to reports.

Bieber was outspoken about his feelings toward people who wait outside his home in a social media post in 2020.

"How can you convince yourself it's not completely inappropriate and disrespectful to wait outside my home to gawk, stare and take pictures as I walk into my apartment," he wrote at the time. "This is not a hotel. It's my home."

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Taylor Swift

Taylor Swift at the Grammys

Taylor Swift carries army grade bandage dressing just in case she ever encounters someone violent. (Kevin Mazur)

Taylor Swift has had a number of stalkers throughout her career. Most recently, a Brooklyn man stalked the singer at her NYC home and "across multiple states," according to police.

The man was arrested on July 2 and charged with "stalking and criminal trespass."

"You’re dead you know," the man allegedly spoke into Swift's Tribeca home intercom on June 12. "You’re holding her prisoner and I need to set her free."

Swift once revealed she carries army-grade bandage dressing due to her fear of violence.

"I carry QuikClot army grade bandage dressing, which is for gunshot or stab wounds. Websites and tabloids have taken it upon themselves to post every home address I’ve ever had online. You get enough stalkers trying to break into your house and you kind of start prepping for bad things," she told Elle magazine in 2019.

"Every day I try to remind myself of the good in the world, the love I’ve witnessed and the faith I have in humanity," Swift continued. "We have to live bravely in order to truly feel alive, and that means not being ruled by our greatest fears."

Sandra Bullock

Sandra Bullock at the "The Lost City" premiere

Sandra Bullock hid from a stalker in a closet after he broke into her home.

Sandra Bullock hid in her closet after a man, who had been stalking her for days in 2014, successfully broke into her home.

"It was the one night that Louis wasn’t with me," Bullock recalled about the moment, referencing her son who was 4 years old at the time.

"It was the one night that our nanny goes, 'Let me just take him to my apartment, which is up the street, because you’re going to be out late.'"

The man died in 2018 by suicide amid a standoff with police at his home, according to Buzzfeed.

Keira Knightley

Keira Knightley arrives at the Oscars

Keira Knightley's stalker meowed at her through the letterbox after showing up at her home. (Reuters)

Keira Knightley was stalked by a man who showed up at her home and meowed at her through the mailbox. She later feared for her and her family's safety after the same man wrote a series of threatening tweets targeting Knightley's husband, James Righton.

"My campaign of disobedience continues in Canonbury tonight. JR and KK are not going to get much help from the police," he wrote under a different name.

"If Righton iz play the devil, maybe i iz play public executioner yah? Of course not iz death threat."

"Righton got too big for his boots last week. I iz cut him down to size yah?"

The stalker was arrested in 2017 and sent to a psychiatric hospital indefinitely, according to reports.

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Kendall Jenner

Kendall Jenner at a 2018 Oscars party

Kendall Jenner was once confronted by a stalker outside her California home. (Reuters)

Kendall Jenner was confronted by one of her stalkers in 2017. The model was inside her car in her driveway when the man approached the vehicle and knocked on the window.

"I turned my car off, and I'm about to open my door, and he's standing right there. He goes, 'I need to talk to you,' and I was like, ‘No, you need to leave,’" she recalled. 

"I called one of my friends sobbing, crying – he's at my window, banging at my window, screaming at me."