Chris Hemsworth and Elsa Pataky throw a sweet birthday party for their nine-year-old twin sons

Chris Hemsworth and his wife Elsa Pataky held sweet birthday celebrations for their twin sons Sasha and Tristan at their $30m Byron Bay mansion over the weekend.

The boys turned nine on March 18, and were treated to a delicious chocolate cake.

Thor star Chris shared a tribute to his sons alongside a photo of Elsa, 46, slamming one of their son’s faces into their cake.

‘Happy 9th birthday to my two little men! Only one way to eat cake in this house and that’s to have mum slam your head into it face first!!’ he captioned his post.

‘”Hey mum I don’t like chocolate cake I prefer vanilla,”‘ he teased. ‘”Oh really son, what about now?”‘ 

In the photo, the actor, 39, smiled as he watched the prank from a slight distance with his hands on his hips.

He was dressed in a grey tank top and camo shorts while sporting a black cap.

Chris and Elsa’s daughter India Rose, 10, was also there to celebrate and helped her mum with the cake faceplant. 

Sasha and Tristan Hemsworth turned nine on March 18, and were treated to a delicious chocolate cake

Fans took to the comments to gush over the picture perfect family. 

‘That is a proud dad stance right there,’ one follower wrote, while another added ‘proud dad moment’.

‘Love it, on ya Mum. Happy birthday boys,’ another commented.

Chris enjoys spending quality time with his two boys and is often seen taking them on little surfing trips to local beaches near Byron Bay and skateboarding 

Chris enjoys spending quality time with his two boys and is often seen taking them on little surfing trips to local beaches near Byron Bay.

The former Home and Away star also encourages them to do other activities like mountain-biking and skateboarding.

When Sasha and Tristan turned eight last year, Chris shared an adorable throwback of his twin sons both dressed up as his Marvel character Thor – wielding their own Mjollnir, the hammer of the thunder god.

When Sasha and Tristan turned eight last year, Chris shared an adorable throwback to Instagram account of his twin sons both dressed up as his Marvel character Thor – wielding their own Mjollnir, the hammer of the thunder god 

‘Happy 8th birthday to my boys! If your asking if they’re allowed to wear any other super hero outfits besides Thor the answer is no,’ he wrote.

Chris and Elsa also share a daughter, India Rose.

The married couple met in early 2010 and tied the knot in December that year.

The family of five live in Byron Bay, on the NSW North Coast, in a mega-mansion estimated to be worth $30million, after relocating from Los Angeles in 2014. 

The family of five live in Byron Bay, on the NSW North Coast, in a mega-mansion estimated to be worth $30million, after relocating from Los Angeles in 2014