According to The Mirror, the 36-year-old's images have been downloaded to a website that boasts it "specialises in explicit celebrity leaks."
The hackers claim they have more photos of the actress that they are threatening to reveal in an "upcoming leak." According to The Sun, they have captioned this threat: 'Busty British actress Hayley Atwell appears to have just had the nude photo above leaked to the Web as part of a preview for the upcoming leaking of her full set.'
Atwell has recently surged into the spotlight after she was hired into the Captain America movies. Sources tell the Daily Star that the security breach has been a "nightmare" for the Hollywood actress.
They have claimed, "In recent years, [Hayley] has hit the big time in Hollywood, so this is the last thing she will have wanted to happen."
She is just one of several Hollywood celebrities who have recently fallen victim to such a crime. Four years ago, Hunger Games star, Jennifer Lawrence, had naked photos of herself circulating on the internet. Kirsten Dunst and Kate Upton also had nude images stolen from their iCloud accounts and shared online that same year.
In 2017, Lawrence expressed her feelings towards the violation to the Hollywood Reporter.
"When the hacking thing happened," Lawrence said. "It was so unbelievably violating that you can't even put it into words. I think that I'm still actually processing it."
"I feel like I got gang-b—ed by the f—ing planet," she continued. "Like, there's not one person in the world that is not capable of seeing these intimate photos of me."
She added, "You can just be at a barbecue and somebody can just pull them up on their phone. That was a really impossible thing to process."
Edward Majerczyk is the hacker responsible for her leak and was given nine months in jail back in January 2017.
As for Atwell, MailOnline has contacted a representative for the actress for comment, however, that is still pending a response.
The Captain America actress made her big debut in a Woody Allen movie, Cassandra's Dream. She played Angela Stark in the movie — which was her first role in a major motion picture. But the Me Too movement and Time's Up campaign gave her the courage to speak up, alongside other actresses, vowing to never work with Woody Allen again.
She has since gone on to star in The Duchess, the live re-make of Cinderella and is now widely recognized as Agent Peggy Carter in the Marvel franchise Captain America. She also appeared in Avengers: Age of Ultron, Ant-Man, the TV series Agents of S.H.I.E.L.D and Agent Carter.
Most recently, she appeared alongside Ewan McGregor in the 2018 release of Christopher Robin when she played Christopher's wife, Evelyn.