The 44-year-old British model delivered a breathy rendition of "Happy Birthday" after popping out of a cake at photographer Mert Alas' birthday bash in London.
Moss mimicked the famous performance of "Happy Birthday" that Monroe delivered on president John F. Kennedy's birthday in 1962. Alas captured the moment in a video he posted on his Instagram account.
"Miss Moss," he captioned the clip, adding a black heart emoji.
Alas, who collaborates with photographer Marcus Piggott under the name Mert and Marcus, also shared a photo of Moss online.
"I mean i literally had kate moss came out of my bday cake," he wrote.
Moss has worked with Mert and Marcus for years, including on the Playboy 60th anniversary issue. She discussed her relationship with the duo in an interview with CNN Style in February 2017.
"I trust them. I would never say, 'I don't want to do that,'" the model said.
"Lots of people have their idea of what a girl is, whereas when I work with them, it kind of is more playing," she explained.