Like father, like son, hey?

Well, Ronan Keating and his son Jack were very much alike this weekend while celebrating their birthdays together.

The singer turned the big 4-0, while Jack celebrated his 18th in style.

Ronan's wife, Storm, took to Instagram today to share some pictures from their yacht party (yep, they partied on a yacht) and it looked deadly.

The soon-to-be mother captioned the pictures: "Best night ever celebrating father and son milestone birthdays on the Silver Sturgeon yacht with family and friends.

"Just got a couple of sneak peek pictures, and can't wait to see the rest."

Meanwhile, the former Boyzone star took to social media to send a heartwarming post to his son.

He wrote: "Happy Birthday to the best son a father could dream of. Can't believe it's been 18 years since the day you came into my life.

"I am so proud of you and the young man that you are. You are the coolest cat I know. Love ya son."