The actress wore the actual colorful bejeweled gown Brit sported at Versace's 2002 Milan fashion show to Tuesday night's "It Ends With Us" premiere.
The James Mangold biopic will feature the "Dune" star doing his own singing.
The actor said Mother Monster was "very encouraging" as they worked out a rhythm between their characters.
The singer had to scrap her signature vocal technique for the film. It's called acting folks.
The new documentary 'Getting It Back: The Story of Cymande' tells the story of the British band that quietly influenced much of today's popular music.
The surprise drop-in came after star Ryan Reynolds revealed how the singer gave her blessing to use "Like a Prayer" in the film.
He's kidding, but the "Deadpool & Wolverine" star says he would never, ever do anything to upset his pal.
The two women met during Paris Fashion Week in January, where RihRih boosted the actress' spirits amid divorce proceedings from husband Benjamin Millepied.
You've seen the paddle board pics? Do the math.
The "Blink Twice" star also talked about "annoyingly cool" fiancé Zoe Kravitz -- and her rock star dad Lenny -- on the "Tonight Show."
