On March 24, the couple celebrated their son Malcolm Mulaney's 4-month birthday alongside Olivia's mother, Kim Munn. To commemorate the moment, Olivia and John posted photos of themselves with their newborn on Instagram.
"It's been 4 months since the happiest, chillest baby came into my world," The Rook star wrote in her post. "He wakes up smiling every single morning without fail, he loves bath time so much that he kicks his legs and looks around whenever he hears the sound of the tub filling up, his tiny fists are his favorite things to gum on and he squeals and follows along page by page whenever we read to him."
Along with the sweet caption, the 41-year-old actress, shared a photo of herself sitting on a bed with baby Malcolm in her lap. "Happy 4 month birthday Malcolm," she added. "I love you I love you I love you."
Meanwhile, John shared his own tender moment with his son, posting a photo of the first time he met Malcolm in the hospital. "Four months ago I met a 6 lb boy who changed my life forever," he wrote in the caption. "I love you Malcolm. You are so much heavier now."
On Instagram Story, Olivia shared another sweet moment between the father-son duo. She posted a video of John looking down at Malcolm, who was seen laying down on a couch as he waved his arms back and forth. In the clip, the 39-year-old comedian turned to his son and said, "I love you, Malcolm."
Olivia captioned the video, "Birthday fun this morning before his daddy left for Texas..."
And it looks like the birthday fun continued throughout the day! The Rook star also snapped an adorable picture of Malcolm with his grandma, with Olivia noting in the caption that he was "spending his 4 month birthday with this retired tiger mom."
See more of the new family's wholesome moments below.