Adriana M. Barraza/WENN 1 / 3
Adriana M. Barraza/WENN 1 / 3

Entertainment Tonight -- "It's Always Sunny in Philadelphia" co-creator/star Charlie Day and his wife, co-star Mary Elizabeth Ellis, have welcomed a baby boy just in time for Christmas.

People.com reports that Russell Wallace Day was born at 7:59 p.m. on Thursday, Dec. 15 in Los Angeles, weighing in at 7 lbs., 13 oz. and measuring 21.5 inches long. The boy's first name comes from Ellis's side of the family and also honors a departed friend, while the middle name comes from Day's family.

"We are overjoyed and overwhelmed at the amount of love that ushered our baby into the world," the couple tells People.

Day and Ellis were married in March 2006.

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