People seriously mind blown after discovering Ben Affleck and Matt Damon are actually related

Actors Matt Damon and Ben Affleck are known for being best buddies.

Their long-standing friendship goes all the way back to the 1980s when they were introduced as kids and bonded over their mutual love of baseball and acting.

The pair first together as uncredited extras in the 1989 movie Field of Dreams, before going on to have a well-publicised Hollywood 'bromance' in which they frequently collaborate and support each other in both their personal and professional lives.

Some of their other joint projects include Good Will Hunting, The Last Duel and Air.

But did you know that Damon, 54, and Affleck, 52, are actually distant relatives?

Hollywood best buddies Matt Damon and Ben Affleck actually have a deeper connection than just being friends (Marcus Ingram/Getty Images)

No? Us neither, but the acting pals are said to be tenth cousins once removed, according to the New England Genealogical Society, which may offer some explanation as to why they've always been so close.

Researchers at the society have dug up evidence that both Damon and Affleck are descendants of William Knowlton Jr, an English bricklayer who moved to the US in the 1630s.

Affleck is also shockingly related to former US president Barack Obama and Princess Diana.

After Instagram page @moviemagick shared a post about celebrities you had no idea were related, people took to the comment section to share their shock.

One person wrote: "No way Affleck and Damon are related."

Another said:" DAMON AND AFFLECK ARE WHAT???"

And a third joked: "Is that why Matt has been carrying him all these years?"

It turns out the long-standing pals are also tenth cousins once removed (Mitchell Gerber/Corbis/VCG via Getty Images)

Other celebrity relatives included in the post were Emily Blunt and Stanley Tucci (sister and brother-in-law), Elle Fanning and Catherine, Princess of Wales (21st cousins) and Julia Roberts and Emma Roberts (aunt and niece).

But, it was another set of celebrity relatives that raised eyebrows among some social media users.

The post also revealed that actors Ashley Tisdale - best known for playing Sharpay Evans in the High School Musical franchise - and Elvis star Austin Butler are tenth cousins once removed, just like Damon and Affleck.

However, one user was quick to point out that the pair played love interests and even kissed in the HSM spinoff film Sharpay's Fabulous Adventure.

They wrote: "Ashley and Austin kissed in the Sharpay spinoff. What the f***?"

After making the discovery, Tisdale told Us Weekly: "We’ve had an immediate connection since we met, and we’ve been close friends for years. We even joked about being fraternal twins."

She added: "I texted him as soon as I heard and he replied right away saying, ‘NO F-ING WAY!.’ He was just as shocked as I was. To know this whole time that we’re actually cousins - it’s just so wild."

Even though tenth cousins are pretty far removed from each other, it's still a bit weird to think about...