Hayes will turn 1 on Tuesday.
Morris took to Instagram to share adorable pics from the intimate bash, including a big balloon display, cute Peter Rabbit-themed cupcakes, and a carrot cake from the Flour Flower Bakery.
The singer teased what was in store for Hayes' party while speaking with ET at the GRAMMYs earlier this month.
"We're gonna keep it small, you know, just family. But I want to do a Peter Rabbit theme, because that's the book that we read to him every night since he was a little newborn," she explained. "So, I would like to do carrot cake and he's gonna have a smash cake and all of the stuff ,but we'll make it cute."
"It's obviously still not safe to have like a huge brawl, but I think it's gonna be adorable," she added.
Morris also gushed that welcoming Hayes into the world has changed her and Hurd "for the better."
"It has definitely changed us for the better. I think it just makes you even more insightful and thoughtful of someone else's existence outside of your selfish own needs," she shared. "So, I think it has just brought us closer and we just love our little guy so much."
See more in the video below.