It's all about that bass baby.
"This sweet baby boy's due date was today on Valentine's Day. We got to meet him Monday, Feb 8th!" Trainor wrote on Instagram on Sunday, alongside photos of the couple's son. "We are SO IN LOVE [crying emoji]. Thank you @darylsabara for the best Valentine's gift ever! Welcome to the world Riley!"
In one pic, baby Riley sleeps peacefully while zipped up in a SNOO Smart Sleeper bassinet. He is also shown close up, peering at the camera. Another pic shows Trainor meeting the couple's son for the first time and another image shows Sabara feeding Riley a bottle.
The proud dad posted the same photos on his own page, writing, "Riley 7lbs 8oz 2/8/21 ps- @meghan_trainor you are my forever Valentine and I'm so beyond grateful for you bringing our son into the world [red heart emoji]."
In October, Trainor, 27, spilled the news that she was expecting on Instagram.
"You all know how long I've wanted this!!!!" Sabara, the actor best known for "Spy Kids," told her at the time, "I love you @meghan_trainor and I can't wait to start a family with you."
Trainor revealed the sex of her baby on Kelly Clarkson's show later that month.
"We've never told anyone... I saved it for you Kelly, I love you," she said before sharing that she was having a little boy.
The "Dear Future Husband" singer had a rather difficult pregnancy. She announced on Dec. 2 that the parents encountered a "little tiny bump in the road" when she was diagnosed with gestational diabetes, which can cause high blood sugar that can be managed with healthy food and fitness.
Trainor told TODAY, "It's manageable and it's OK. And I'm healthy and the baby's healthy." She felt that it was "nice to learn so much about food and health" during her maternity journey.
A week later, the Best New Artist Grammy winner gave fans a health update, saying, "I basically just watch what I eat now, I write everything down, I check my blood and we're good now... I've been crushing it."
She also admitted on TODAY that the holiday season was especially hard because of COVID-19.
"It's definitely harder with quarantine to be creative at home and then, because we're pregnant, we don't drink, we don't party, we don't celebrate," the new mom explained. "And so our next thought was like, 'OK food, like, let's go in,' but now with the gestational diabetes, we have to be like, 'let's count every carb that we eat.' At this point, I don't know what we can do to celebrate."
Through it all, her one major fear was not having her mom Kelli Trainor in the delivery room due to pandemic protocols.
"I'm scared of birth and, like, not being able to have my mom in the room," the musician said in a recent radio interview. "'Cause, like, they can barely let your husband in the room, but I'm like, 'But I need my momma.'"
But she made some positive memories during her pregnancy, too. For her and Sabara's second wedding anniversary in December, the couple shared some new baby bump pics on social media. As the singer wrote to her love, "Thank you for giving me the best gift ever."