The Today Show host confirmed in March that his eldest daughter, Courtney Roker Laga, is expecting her first child with husband Wesley Laga.
At the time, he revealed that he learned of her pregnancy by accident, when his son-in-law's brother accidentally made him aware of the news, and now a similar slip up, this time from Courtney herself, led him to discover the sex of the baby, who is due in June.
Al had previously expressed to his daughter that he wanted the sex of his first grandchild to be a surprise, but the secret didn't last very long.
The beloved weatherman spoke to Entertainment Tonight on the red carpet, as he was honored at the Broadcasting and Cable Hall of Fame Awards' 31st Anniversary Gala in New York City on Wednesday, and explained the slipup.
"Courtney is expecting our first granddaughter," he said, before quickly reverting to using "grandchild."
He then explained that while he had preferred not to know, after he saw a sonogram picture from his daughter over text, and told her: "That baby looks just like you," Courtney inadvertently replied with: "Doesn't she?" revealing that she would be having a baby girl.
Courtney, 36, first shared the news of her pregnancy back in March with an Instagram video set to a remix of Mariah Carey's "Always Be My Baby," featuring pictures of the expecting couple along with videos of their sonogram.
"A new adventure is about to begin," she captioned her post next to a baby bottle emoji, and Al along with his wife Deborah Roberts were quick to gush over the special news in the comments section under the post.
He excitedly commented: "Here we go!!! So very very happy!!!!! You guys," adding: "Going for Pop-Pop," while Deborah, who is Courtney's step-mom – her mom is Al's ex-wife Alice Bell – wrote: "This is so very exciting!!!"
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