Reps for the couple say that both mom and baby are healthy and well, and dad is "ecstatic." As for the name, Silas was the middle name of the "Suit and Tie" crooner's maternal grandfather Bill Bomar, who died in 2012. Randall is Timberlake's own middle name, and his father's first.
The popular celebrity couple managed to keep Biel's pregnancy under wraps for the full nine months, confirming the great news on the singer's 34th birthday in January.
"Thank you EVERYONE for the Bday wishes! This year, I'm getting the GREATEST GIFT EVER. CAN'T WAIT," he captioned a photo of himself kissing Biel's fully formed baby belly.
Congratulations to the happy new parents on their new bundle of joy!
(Photo: Kevin Mazur/Getty Images for GQ)