Justin Timberlake "is so excited" after becoming a father for the first time.

Justin Timberlake and Jessica Biel

Justin Timberlake and Jessica Biel

The 'Not a Bad Thing' hitmaker, 34, is reportedly bursting with pride since wife Jessica Biel gave birth to their son, Silas Randall Timberlake, last weekend.

A source close to the couple said: "Justin is so excited, he doesn't know what to do with himself!"

The 'Accidental Love' actress, 33, is also over the moon about their new arrival.

The insider told Us Weekly magazine: "Jessica sees herself as a mom of boys, so it worked out perfectly."

The duo are quieting adjusting to parenthood at their home in the exclusive Yellowstone Club in Big Sky, Montana.

The source said: "Their house is all set up for the baby. They want to raise him out of the spotlight."

But they plan to return to their Hollywood Hills mansion in the near future when Jessica opens her new restaurant, Au Fudge, in Los Angeles.

A second source explained: "Jess is opening her kids' restaurant, Au Fudge, near L.A. in five months and has tons of meetings."

The pair are getting support from friends and family members, including Justin's mother, Lynn Harless, who is completely smitten with her new grandson.

The friend said: "Lynn jokes she wants Silas all to herself!"