Andy Cohen welcomes baby boy: 'I'm speechless!'

Andy Cohen is officially a father!

The 50-year-old "Watch What Happens Live" host took to Instagram late Monday night to announce the birth of his first child, son Benjamin Allen Cohen, who was born via surrogate on Monday evening.

"WOW! This is my son, Benjamin Allen Cohen," he captioned a black-and-white photo of himself holding his baby. "He is 9 lbs 2 ounces!!" 20 inches!! Born at 6:35 pm, PT."

He went on to reveal that the name he chose for his first child has a special meaning.

"He is named after my grandfather Ben Allen," he went on. "I'm in love. And speechless. And eternally grateful to an incredible surrogate. And I'm a dad. Wow."

SEE ALSO: Real Housewives react to Andy Cohen's baby announcement

Cohen has been living in Los Angeles as he awaited the birth of his son, and he's been filming "WWHL" from a temporary studio there. He normally lives in New York City.

The Bravo personality had revealed that he was expecting a child in a surprise announcement on his show last December, when a slew of original Real Housewives were guests.

"Tonight, I want you to be the first to know that after many years of careful deliberation, a fair amount of prayers, and the benefit of science, if all goes according to plan, in about six weeks' time I am going to become a father," Cohen said at the time. "Thanks to a wonderful surrogate who is carrying my future. Family means everything to me and having one of my own that I have wanted in my heart my entire life. And though it's taken me longer than most to get there, I can't wait for what I envision to be the most rewarding chapter yet."

Last month, all of the Real Housewives threw Cohen a lavish baby shower at The Palm in Los Angeles, with clips from the celebratory affair going viral on social media. A few days later, he celebrated his impending fatherhood with close pals Kelly Ripa, Sarah Jessica Parker, Anderson Cooper and more.

Mazel to Andy!