Justin Timberlake reveals pics of baby Silas on 'Tonight'

/ Source: TODAY

Not only did Justin Timberlake wow "Tonight Show" audiences on Wednesday night with his "History of Rap 6" with host Jimmy Fallon and by successfully judging the "Lip Sync Battle" between Fallon and Ellen DeGeneres — he had a secret weapon in his back pocket.

Rare baby pics of 5-month-old Silas Randall! Timberlake and wife Jessica Biel welcomed the bundle of joy earlier this year.

Those eyes! That lopsided smile!

And Timberlake revealed some amazing news: Silas' first word actually has been uttered ... and it was "Dada!" Which Fallon, who literally wrote the book on getting your baby to say "Dada," was darn pleased about.

Follow Randee Dawn on Google+ and Twitter.