Bryce went on to write: "Named after his bright personality, this gorgeous little boy is now part of our soon to be family."
It comes ahead of the gender reveal for the couple's unborn twins, which is set to be shared Friday night.
The post featured several photos of Bryce and Melissa with their new pup at their family home, and they couldn't be more excited with their newest family member.
Melissa also shared a post dedicated to Sonny, and penned a similar message to Bryce: "It’s #InternationalDogDay & because we never do anything by halves 😂 we would like to introduce you to someone very special… Meet Sonny!"
"Our 9 week old Border Collie, who we recently adopted (as he needed a new home)… he has a gorgeous personality, cuddles the babies already, and is a loving part of our soon to be family of 5," she wrote.
"PS. our gender reveal is coming! Tomorrow in fact! I had a follow up appointment today after a bit of an issue with appointments this last week so we’ve held off for one more day xx."
The couple have been teasing the gender reveals over the past few days, where Bryce revealed that Melissa had taken the Harmony Test and the results came back all clear.
"PLUS we found out the gender of one of the twins.. but couldn’t get a definitive result for the other," he said at the time.
It looks like they've finally managed to find out both genders, and fans can expect to be in the loop very soon.
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