People are in stitches over Ryan Reynolds' social media post to Sandra Bullock for her birthday.

Most of us get an embarrassing picture or two of us slightly worse for wear on a night out from our friends on our birthdays, but Deadpool star Reynolds didn't hold back for Bullock's 59th yesterday (Wednesday 26 July).

And the funniest part is Bullock doesn't even have Instagram, so while she's likely seen the post, she can't even respond to it in the comments.

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Reynolds' post shows a clip from 2009 rom-com movie The Proposal.

In the film, Bullock plays Margaret Tate, the editor-in-chief of a big publishing company, with Reynolds starring as her assistant Andrew Paxton.

The footage shows Bullock's character racing out of the bathroom, fresh out the shower after an altercation with a dog.

Alas, in her hurry she runs straight into Reynolds' character and the pair fall in a heap of exposed limbs - appearing completely butt-naked - on top of one another on the floor.

Reynolds' caption reads: "Happy Birthday to the inimitable and stunning Sandra Bullock!

"For your birthday this year, I got us both intimacy coordinators. And an HR department. And clothing?"

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Fans of the actors have flooded to the post finding the birthday tribute absolutely hilarious.

One social media user said: "Who else read this post in Ryan Reynolds voice?"

"The horror when Sandra Bullock sees this for a birthday wishing post," another joked.

A third commented: " I almost peed myself laughing from that scene. Best movie ever!"

And a fourth added: "I bet this scene is an inside joke between these two actors after so many years. Happy birthday, Sandra Bullock."

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Bullock has previously spoken out about the naked scene, noting it was actually a whole lot less awkward to film than you might have initially thought.

On About Last Night Podcast, she told host Adam Ray that Reynolds and her have 'known each other since [they] were prepubescent'.

"We go way, way, way back," she added.

The actor also made clear she would only film a naked scene if she could be 'humiliated and funny'.

She explained: "You will not see me trying to attempt being sexy naked - in real life or onscreen. There's just no point in it!

"It was for that reason, with a friend that you trusted comedically, and safety-wise I knew I was in the presence of safety."

And FYI, the pair weren't fully butt-naked, they were wearing 'these flesh-coloured things stuck to [their] privates' and Bullock's hair was placed 'strategically over the nipples'.

Getty Images/ Gregg DeGuire/FilmMagic

Unfortunately for Bullock, Reynolds' birthday is still quite a stretch away (23 October) so she's got a while to wait until she can dig up some dirt on the star and post it online herself.

But on the other hand, at least she has plenty of time to plan the perfect way to get him back.