Baby Maguire weighed in at 7lbs, 1 oz, and has some artistic inspiration behind his name, Leo James Maguire.
"His name was inspired by DaVinci, who I’ve been a lifelong admirer of,” Maguire tells ET exclusively. “We are so grateful to our amazing doctor Purlow and all the staff at the hospital.”
The couples first son, two-year-old Flynn, is ready for his big brother duties.
"Flynn's very excited to meet his little brother and give him cuddles,'" Maguire tells ET. "And [he] says he'll 'teach him about Star Wars and football.'
Maguire played the dashing Robin Hood on Once Upon a Time, but hasn't appeared in the newly rebooted season 7. However, his cast mate and real-life friend Colin O'Donoghue, aka the dreamy Captain Hook, is hopeful.
"I'd be delighted if Robin Hood showed up in Hyperion Heights," he told ET in October. "I don’t know if that's going to happen or not, but we'll see. It'd be great."
"Fingers crossed," he added with a smile.
For more on Once Upon a Time, watch the video below!