One Direction's Louis Tomlinson Welcomes a Son

— -- Louis Tomlinson is a father!

The One Direction singer, who welcomed a baby boy on Friday with Briana Jungwirth, announced the news Saturday.

"I'm pleased to say my baby son was born yesterday :) He is healthy and pretty amazing :) I'm very happy!!" he wrote on Twitter, before adding, "Daddy daddy cool."

Tomlinson, 24, and Jungworth, a stylist, dated briefly in early 2014 and, according to People, remain close. It was revealed last summer that they were expecting. This is the first child for both.

"Louis is happy and very excited about becoming a dad and he thinks Briana will be an amazing mother," a mutual friend told the magazine. "It was a surprise at first, but he and Briana are very, very close friends and this has brought them even closer."