"It was just a post about Meghan and Prince Harry," Pilot said.
"I'm not the person who sold the house. I don't know who sold it."
However, another source claimed the property had recently sold, and asked whether the Sussexes were the buyers, said: "Non-disclosure agreements have been signed. But you're very warm."
Harry and Meghan moved to the US from Canada shortly before coronavirus lockdowns came into effect.
The couple were reportedly looking for a home in Malibu, 50 km away from central Los Angeles.
The stunning home showcases ocean views, two pools, an "exceptional" kitchen, five acres of grounds, a gym and membership to a beach club. It was renovated in the past 18 months.
A source said: "It is fabulously beautiful, so maybe they took one look in there and wanted to have it. It's very private. There's nothing on the market like it."
Gibson, 64, became known for his roles in Mad Max and Lethal Weapon movies in the 1980s, winning two Oscars for starring in and directing Braveheart in 1995.
X-Files star David Duchovny is also a previous owner.
A source close to the Sussexes said that rumours they had bought the house were "categorically untrue".