Former Playboy models Holly Madison and Bridget Marquardt, who are both ex-girlfriends of founder Hugh Hefner, believe the Playboy Mansion is haunted.

Madison and Marquardt appeared as guests in the Thursday episode of the Discovery+ series "Ghost Adventures," where they talked about their spooky encounters in the famous 29-bedroom mansion.

On the day the episode aired, Nylon also published an interview story detailing the two models' experiences while living with Hefner on the property in the 2000s.

"You definitely felt the nostalgia and the old energy," Marquardt said of the 5.3 acre-mansion situated in the affluent Holmby Hills in Los Angeles. "I had little things happen."

Marquardt went on to say that sometimes TV channels or the volume would randomly change. She also opened up about that one time she had seen a woman standing in the doorway of her closet looking into her room. She gasped and turned for a better view, only to find out that the woman had disappeared.

According to Marquardt, the woman was "very pale and very thin" and had "long, black stringy hair."

"She was wearing a white T-shirt that was too big on her and black acid wash-y jeans. She was more modern-day and I feel like I recognized who she was," "The Girls Next Door" star said.

Marquardt said the ghost might be the spirit of Joanie, a staff member who helped the women staying in the mansion and took care of the pets in the house. Joanie had died of cancer before Marquardt moved in.

"There was a new pet in the house, and she was just seeing what was going on. I think it was a loving thing, but it's scary because it's shocking," she said further.

Madison, who lived in the mansion as Hefner's girlfriend from 2001 to 2008, also had her share of paranormal experiences.

While in the basement gym, she reportedly saw a woman coming out of the bathroom and then crossing in front of her and out of her line of vision.

According to Madison, the woman looked modern and wore a hot pink sports bra paired with a pair of black workout pants, making her look like a Playmate doing photo tests.

Madison walked around the corner to check where the woman had gone to and saw another door. Thinking the woman might have come that way, she opened it. But to her surprise, she found out it was actually a closet. It was then that she realized the woman had practically vanished.

The ghosts of the Playboy Mansion were also featured in "The Girls Next Door" Season 1, Episode 10, in which Marquardt hired a paranormal investigator and a medium to do a seance in the mansion. The investigator reportedly found high levels of paranormal energy in various parts of the house, particularly in Marquardt's room.

"Ghost Adventures" follows the paranormal investigations of Zak Bagans and his team of experts as they explore haunted locations.

Hugh Hefner and Holly Madison
Holly Madison claimed on her memoir that she saw Hugh Hefner's last will and testament. Pictured: Hefner and Madison pose during a press conference introducing the new season of Hefner's TV show "Girls of the Playboy Mansion" on E! Entertainment on Jan. 11, 2007 at the Palyboy Mansion in Beverly Hills, California. Getty Images/Gabriel Bouys