While Timberlake confirmed the news this week, a close friend of the couple accidentally let it slip back in 2020.
Lance Bass, from Timberlake's former band NSYNC, confirmed the news in an interview with Entertainment Tonight.
"The baby is cute of course; it's Justin and Jessica!", he revealed during a conversation about his podcast, The Daily Popcast.
But when the subject of the baby's name came up, Bass knew that he may have shared too much. "That's a good question," he said. "Justin would kill me!"
Another close friend of the couple, Timberlake's friend and collaborator Brian McKnight also spilled the news to Hollywood Life, confirming that the rumours were true.
"I think if he’s going to do music, he's going to make sure that that’s secure, and then he'll bring us into his music," he said. "And being inspired! He just had a new baby. I think that's going to be really inspiring for him and he’ll have some new music based on that, I'm sure."
The Daily Mail reported back in July that the two had their new baby in Montana, where they've supposedly been staying throughout the coronavirus pandemic.
Both Timberlake and Biel have also recently commented on parenting their son, Silas. Back in June 2020, the singer shared a message about raising his son and being a role model in light of the ongoing racial injustices brought to global attention following the death of George Floyd.
"Boys grow up to be fathers. I think about that a lot these days. We try to teach our son to love and to respect everyone—we teach him that all people are all created equal, and that no one should be treated differently because of the colour of their skin," Timberlake told People, where he went on to praise his wife.
"I'm grateful for my wife, who made me a father, and is my favourite person/partner/teacher/friend in all of it. I'm grateful for my son, who is always ALWAYS teaching me right back."