Amid the congratulatory comments on social media, a few users wondered if the couple decided to have a child to save their marriage with a "band-aid" baby.
"Well that's one way to fix things," said another.
"Wish I could be happy for them...but no one needs five children. There are too many people in this world as it is. The world can't support the reproductive rate at this pace," someone else wrote.
"Thank you for contributing to the over population of the planet," another wrote. "I hope this one will be your last and you will use wiser judgement."
Another person simply posted an emoji of a face rolling its eyes and another nauseous emoji.
Some defended the famous couple from the negative comments.
"I'm appalled at the negative comments here! This is a great married couple who love their existing children and seem to be wonderful parents. Why make such mean comments???" one person wrote.
Chip announced the exciting news via Instagram after Tuesday night's Fixer Upper episode following a day of dropping hints online, including a video of him and Joanna chanting "number five."
"Gaines party of 7.. (If you’re still confused.. WE ARE PREGNANT)" Chip posted under a photo of the couple sporting their respective bumps, only one of which is from a baby.
The contractor and dad of four shared how their next baby came about in a tweet, writing, “You might recall a few months back.. the ever amazing, ever romantic [Johnny Swim] was in Waco. And they put on a little too romantic of a concert.. anyways, one thing led to another, & we are officially pregnant. And I could not be more EXCITED!”
Joanna even shared a sweet video ultrasound of the baby's heart beating, in which she says Chip "swears" the baby is a boy.
The HGTV couple is already parents to two boys and two girls, Drake, Ella Rose, Duke, and Emmie Kay.
The pregnancy may be part of the reason the couple decided to end their hit show after the ongoing fifth season, announcing in September that they wanted to spend more time as a family.
Photo credit: Instagram / @joannagaines