Watch: Ryan Gosling crashes Greta Gerwig's gym class with Ken flash mob

Ryan Gosling arranged an uncanny Barbie-themed surprise for Greta Gerwig’s 40th birthday by ambushing her with a Ken flashmob at her gym.

The official Barbie film account on Instagram shared a video on Friday, Aug. 4, in which a flash mob of dancers dressed as Ken arrived during the filmmaker's pilates class to perform a routine set to Gosling’s song from the film, I’m Just Ken.

"As Kens know…. Sometimes the only way to express your feelings is through song & dance," the caption read.

"Ken Ryan sent these special Barbies and Kens to start Greta’s birthday with all the feelings!!"

The Little Bird director could be seen from afar as she horridly took in the set before breaking into laughter with tears.

The Kens’ performance was followed by a bunch of women dressed in pink appearing as Dua Lipa’s Dance The Night began blasting from the speakers.

At the end of the clip, both Kens and Barbies joined to perform a choreographed dance to the chorus of the pop hit.

The flash mob was apparently booked from BookAFlashMob.com by the Notebook actor.

Gerwig’s birthday came side by side with the record-breaking success of Barbie, which is very close to hitting $1 billion at the box office worldwide. This feat hasn’t been achieved by any female director so far.

Meanwhile, Gosling achieved his first-ever Billboard Hot 100 ranking with the release of his debut song, I’m Just Ken, from Barbie: The Album.