The mother-of-two is expecting her third child with husband Brian Fichera, who will join their two sons Oliver, 16 months, and Calvin, four.
"I'm holding my stomach and I don't have to hold it in anymore," she joked during the show's third hour.
VIDEO: Today show's Dylan Dreyer reveals she's pregnant!
She added: "We really enjoy having kids. Calvie and Ollie, they're so much fun. And we're like, 'Let's try for a third.' And it wasn't happening so we said, 'Let's forget it, let's move on.' And then, of course, surprise!"
Savannah Guthrie had the best response to the happy news, telling her co-star that the baby should be a girl. "I just want you to have a girl, but I bet it's a boy," she said.
Today's Dylan Dreyer announced her pregnancy news to her co-stars
The comment went down a treat with viewers, with one writing on Twitter: "Omg! Congratulations on being pregnant again @DylanDreyerNBC! 3rd child! That's great!
"I like how @SavannahGuthrie said that the child should be a girl! We need another female figure you know!"
Another viewer wrote: "Congratulations, such happy news!" while a third added: "This is such happy news!"
Dylan's baby is due in November, and she can't wait to meet them.
Savannah Guthrie had the best response to her co-star's happy baby news
The TV star often shares relatable parenting posts online and recently posted a picture of her "messy living room" after Oliver had been playing in it.
The star's baby news follows shortly after she was able to reunite with her parents for the first time in a year after getting her first dose of the Covid vaccine live on the Today show in April.
The new baby will be joining brothers Calvin and Oliver
The happy news meant that her mom and dad were able to see their grandchildren again – having only met Oliver a handful of times before the lockdown.
The presenter also recently went on a date night with her husband in New York, but admitted that they had gone out a little earlier than usual – having sat down at a table at 5pm.
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