Happy ... aaaaggghhh! Adele showed off pal Nicole Richie's prankster side with a belated birthday message on Instagram Saturday (Sept. 26).
In a video clip, Richie -- who turned 39 on Sept. 21 -- is crouching by the oven while a male friend chats. 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.