The video of Gage and Gaines was recorded during the Tim Tebow Foundation Celebrity Gala and Golf Classic in Ponte Vedra on Saturday.
The Fixer Upper stars made the announcement via a video Chip tweeted on Wednesday (March 7).
"We're just about to have another little baby because Uncle Chip lost his mind ..." Chip and Gage revealed that Joanna is indeed carrying a boy and they're going to give him a name that starts with the letter "D". "I don't know. That might not even be allowed on Twitter", the HGTV star was speaking to the little boy. "Can you help me think of a "D" name?" So far, Chip only came up with the name Dragon, which elicited quite a giggle from Gage.
Chip and Joanna already share 12-year-old son Drake, 11-year-old daughter Ella, 9-year-old son Duke and 7-year-old daughter Emmie.
Oh, and one more fun thing we got to see this weekend is a more obvious baby bump on Joanna, free from flowy dresses. Although she didn't appear in the Twitter video, Joanna joined Chip at the charity event, and the two had an "amazing weekend".
"What an incredible weekend with the @timtebowfoundation", she wrote.
The happy spouses have been starring on Fixer Upper since 2013. "I don't know", Gaines said in the clip.