The former Boardwalk Empire star welcomed his first child with actress Rose Byrne last year (16), but the couple has gone to great lengths to keep little Rocco out of the spotlight, with Bobby frequently posting social media images of their kid with his face partially shielded from full view to protect his privacy.

However, Bobby couldn't hide his pride on Wednesday (01Feb17) as he shared a shot of himself cuddling up to Rocco as they enjoyed a day at the beach in Rose's native Australia.

He captioned the snap, "Happy Birthday my beautiful boy".

Bobby and Rose began dating in 2012, and they have recently been dogged by rumours suggesting they are heading down the aisle, after the Bridesmaids star was photographed wearing what appeared to be an engagement ring on her left ring finger in November (16).

Representatives for the actors have remained silent on the speculation, but the couple has been enjoying life as a family of three.

The actress previously opened up about adjusting to life as a new mum, admitting she rarely left home in the first few months after Rocco's birth because she was so exhausted.

However, she was grateful to have Bobby by her side as she has learned a great deal about parenting from her man.

"He's terrific," she smiled to news.com.au in May (16). "He has a 21-year old (from a former marriage) so this is old hat to him. And I have to say, having someone who's already a parent is great because this is all very, very new to me. So I'm just taking tips from him."