The year was 1989. Ricci was filming the movie "Mermaids" with Winona Ryder, the actor's girlfriend at the time, and she recalled witnessing a possibly anti-gay confrontation between two other people on set.
"Johnny is actually the person who explained to me what homosexuality was when I was 9," Ricci recently told Andy Cohen on SiriusXM's "Andy Cohen Live." "There was something going on on-set and someone was not being nice to someone else. And they were like, 'Oh, well he might be homophobic.' And then I was like, 'Well, I don't understand what that is.'"
The "Yellowjackets" actress continued, "I was in Winona's trailer and... she put me on the phone with Johnny. And Johnny explained it to me."
Ricci said Depp used "the simplest terms" to define homosexuality. "He was like, 'It's when a man wants to have sex with a man and when a woman wants to have sex with a woman,'" the 42-year-old recalled. "I was like, 'Ah OK.'"
E! News has reached out to Depp's rep for comment and has not heard back.
During the Radio Andy interview, Cohen pointed out that the actress could have asked another "Mermaids" co-star about the concept. "I mean, you've got Cher in the next trailer," he joked, referring to the movie's lead star. Ricci responded, "I know, we should've run right over there."
Ricci would go on to star with Depp himself in a number of movies -- "Fear and Loathing in Las Vegas" in 1998, "Sleepy Hollow" the following year and "The Man Who Cried" in 2000.
The two also appear in Boris Acosta's upcoming Depp documentary "Johnny's Inferno." The project, set for release in October, focuses on the star's personal life struggles and is the latest in the director's Dante's Inferno series of films.
Depp dominated headlines this summer with his defamation trial against ex-wife Amber Heard. The jury ruled that the actress was liable for defaming the actor with a newspaper op-ed and ordered her to pay him more than $10 million in damages. Heard also won a smaller legal victory with a countersuit and Depp was ordered to pay her $2 million because his lawyer had accused her of perpetrating a "hoax."