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“Every day is a new milestone,” Pratt told reporters on the red carpet at the 2014 March of Dimes Hollywood Luncheon on Friday.
“He’s starting to say ‘please’ and ‘thank you.’ [He’s] very polite. He pointed out baby Jesus on our nativity. That was sweet.”
He added, “He’s just in the process of getting potty-trained now. That’s an adventure. [It’s] frustrating and rewarding all at the same time.”
Beyond Jack’s handful of latest milestones, Pratt and wife Anna Faris have more incredible reasons to be proud parents.
During the star-studded lunch celebrating premature babies, Pratt took to the podium in the center of the room to share a moving story about their son, who was born nine weeks early in August 2012.
“Our little Jack didn’t want to be an October baby. He wanted to be born in summer, I guess. Anna woke me up in the middle of the night and she told me that her water had just broke. It was two and a half months early. Oh baby. Ready or not,” Pratt shared.
“We went to [the hospital] … She stabilized and we waited, we prayed, we contemplated the faith of our unborn son.”
Pratt, 35, said the doctor gave the family a goal: “To make it 30 more days.”
Faris did her best to entertain herself while she waited for their son to arrive — starting with a collection of Mad Men DVDs.
“Thank you Jon Hamm. If we hadn’t already named him Jack, we would’ve named him Jon Hamm,” Pratt joked, garnering laughs from the event’s guests.
Pratt noted that during this time he turned to “a few close friends” and his “friends at Parks during the day” for support.
“We didn’t make it 30 days,” the Guardians of the Galaxy star explained. “We made it seven and then he came, just about nine weeks early and he’s 3 lbs., 12 oz. Anna could hold him for a moment and then it was off to the NICU.”
And the actor — who opened up to PEOPLE earlier this year about how his son “restored his faith in God” — added how the couple really embraced skin-to-skin contact while they were in the hospital.
“It was just the best feeling I’ve ever had,” Pratt shared. “My little boy just laying across my neck and my chest, and feeling my heart beat and feeling the love. I played him country music and I sang to him, and I made him promises in that moment … about what kind of dad I wanted to be and I just prayed that he’d live long enough to let me keep them.”
Faris, 38, also had her own personal struggle as she started motherhood.
“My wife had a hard time producing milk,” Pratt said. “She didn’t stop trying. It was very painful, but there is no choice and she stuck to it [with] this type of strong, super-human focus that only mothers have and finally it worked … We needed that win.”
But the family continued to have many more wins: After about one month in the intensive care unit, the first-time parents brought their “little five-pound baby home.”
“Jack went from a small, helpless little squirt to a strong, smart, happy, funny and vocal boy,” Pratt said. “He loves monster trucks and Daniel Tiger. Believe it or not, he loves vegetables — broccoli and cherry tomatoes are his favorite food. He’s a deejay.”
Related: Watch Chris Pratt Get Choked Up Talking About His Son
— Mariah Haas