They've been inseparable since they formed an unlikely friendship while filming last year's season of Married At First Sight.

And on Tuesday, Jason Engler couldn't fight back the tears after he revealed that his co-stars Bryce Ruthven and Melissa Rawson asked him to be the godfather of their newborn twin boys, Levi and Tate.

'I use the term beautiful angel a lot, however Liss is actually deserving of that title,' Jason, 36, captioned an Instagram selfie alongside Melissa.

'One of the most amazing women I have met. There should be a halo hovering over her head. I'm still not sure where she hides her angel wings, but they are there somewhere! Love ya Liss.'   

Jason explained that the selfie had been taken not long after he was 'crying in public' when the couple asked him to be the godfather of their twins.

'I'm not even ashamed about my public tears,' he concluded the post.

The trio had been celebrating Melissa's 32nd birthday alongside their co-star Belinda Vickers at the trendy The Deck Est. 2013 bistro in Port Phillip Bay, Victoria.

Sharing a photo to Instagram ahead of the celebrations, Melissa wrote: 'First birthday as a mummy. Absolutely spoilt by everyone and spent the day with my babies'.

She also showed off some of her gifts, which included several items from luxury brands like Gucci and Hoskings Jewellers, as well as flowers.

'An amazing partner, an amazing mother and my soulmate. Love you more than any words on Instagram can describe'. 

Last month, Melissa spoke candidly about her sleep deprivation while taking care of her twin boys, who she welcomed in October.   

'The sleep deprivation is just next level,' she told her followers. 'You are told by everyone that, 'enjoy your sleep now, you're not going to get any sleep when the baby arrives'... and yes that's very true and I'm aware of that.' 

'If you're planning to have a baby, this should never change your decision about it. You won't be able to comprehend the sleep issue, I certainly didn't.'