Now fans' hearts can be full hearing just how much Chmerkovskiy, 36, loves being a first-time father.
The dancer shared a pic of himself cradling little Shai, who came into the world Jan. 4, and gushed about his little boy in the caption.
"It's been one week plus one day of my fatherhood and I'm the happiest person that's ever lived," wrote Chmerkovskiy, who also revealed that his "protective" instincts have kicked in.
"I don't let too many people come see my son and I don't want to put any of him on social media just yet. (Peta) and I just want to enjoy our little family, together with our loved ones, and take in all the precious moments which we'll never get back," he continued.
"So be sensitive please," he concluded before wishing everyone a great new year. "Ours sure started with a bang."
"P.S.," joked the joyful new dad. "Farts, poops and throw-ups are the best!"
Chmerkovskiy and Murgatroyd, 30, have dated on and off since 2012. They became engaged in December 2015 and announced they were expecting last May.
Chmerkovskiy has strutted his stuff on "Dancing With the Stars" for a whopping 15 seasons, but don't expect him back to the set any time soon.
The star told Bravo last October he was taking next season off to enjoy being a father.
"The baby comes in January and then a month-and-a-half later I would have to be in L.A. to start training with somebody else," he said.
"Trust me, I really don't care how this comes across, but there's no money on the planet that can replace me missing out the three, four, five months of my baby's life," he said. "Zero chance."