Chris Sullivan has become a father for the first time.

The 'This Is Us' actor and his wife Rachel welcomed a son into the world on Tuesday (28.07.20) and have named the little boy Bear Maxwell.

The baby weighed 8lbs 1oz and measured 20.5 inches long.

Chris announced on Instagram: ''HE HAS ARRIVED! ⁣

⁣''8lbs of beautiful baby boy. Witnessing @therealrachelsullivan bring our first son into this world, after 20 hours of labor, was one of the great honors of my life. It was primal and intentional and I have never been more in love with this powerful woman. ⁣

''She and baby are resting and recovering well. Everyone is healthy and exhausted. ⁣(sic)''

The 40-year-old star and his spouse had ''designed a puzzle'' to reveal the tot's moniker to their loved ones as a way to pass the time over the last few months.

He told People magazine: ''As far as the name announcement goes, we designed a puzzle to send to our family members as a fun way to announce his name and to keep us all connected during quarantine -- kind of a group activity to reach across the land. It's both information and something to do. And the reveal of our first son's name.

''Everybody had a great time. It was kind of set up like a contest -- everyone had a time when they could start and everyone had to send us a photo when it was finished.

''Everyone is very excited to meet Bear, and hopefully in the next few months, we'll be able to introduce him to all of his friends and family.''

The couple - who married in 2010 - announced they were expecting their baby on Instagram in January.

They each shared an ultrasound photo on their respective accounts, and confirmed at the time they knew they were having a boy.