Ryan Gosling had the best birthday gift for Barbie director Greta Gerwig 

Barbie had the world on tenterhooks in the months leading up to its release, and now it has hit the big screens it is fair to say that everyone is obsessed. 

From the epic costumes, affordable jewellery brands and simple beauty hacks Margot Robbie followed, to Ryan Gosling's surprising vocals, dance moves and witty one liners, it has well and truly taken over.  

But, there's more. 

Ryan continued his Ken-ergy off-screen to celebrate Barbie director Greta Gerwig's 40th birthday with a surprise flash mob to interrupt her Pilates class. 

A video was shared on the official Barbie movie Instagram account to document the moment, and it's the joy you didn't know you needed. 

The post was captioned: "As Kens know… Sometimes the only way to express your feelings is through song & dance!

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

The upload has racked up over 60,000 likes on the photo sharing site, as well as plenty of praise from fellow social media users. 

One commented: "This movie has reached legendary status."

Another added: "Ryan always the same off set and on! Sweetest soul ever making birthdays the best."

While a third shared: "This movie is going to [make] history!!"

In the footage, Greta can be seen on a Pilates table, before a group of dancers - some channelling their Barbie energy in pink ensembles - strutted into the class. 

As Ken's solo track I'm Just Ken began to play, the dance troop perfected the choreography in the Barbie movie before Dua Lipa's Dance The Night Away blared from the speakers - which saw even more dancers flood through the doors to nail the routine. 

In the background Greta could be heard giggling and saying, "Oh my god!" in shock.

By the end of the video, the creative mastermind was in tears and overjoyed with the surprise birthday gift, though she wasn't sure who arranged the treat.

"That was so beautiful," Greta praised, before she quizzed: "Who are you?"

But a voice behind the camera posed a question to Greta, and said: "Guess who planned this?", to which Greta replied, "I have no idea!"

Not to give the game away too soon, the mystery voice hinted "Think of a bagpiper", which is an inside joke with those on set and a nod to 42-year-old Ryan.

It has previously been reported Greta organised a sleepover for the Barbie cast, and while Ryan - who has daughters Esmeralda and Amada with Eva Mendes - wasn't able to attend, he sent a man to play the bagpipes to entertain slumber party guests.

Sublime.