In a video clip, Richie -- who turned 39 on Sept.
As the "Hello" singer walks into the kitchen, Richie leaps out and yells, startling Adele and causing her to scream!
The 15-time Grammy winner composes herself, then crouches over the TV personality, who is lying face down on the floor laughing!
"For f--ks sake!" mutters Adele as she walks off.
"Happy belated birthday to my daily dose of grace @nicolerichie I admire you and love you so much," the vocalist captioned the Instagram post.
The celebratory post also included a selfie of Adele laughing while Richie is indoors pressed up against a pane of glass, the two snuggling a giraffe as the singer looks terrified, the women glammed up together, and more.