Justin Timberlake proudly shared a new photo holding his son Silas in honor of his first Father's Day on Sunday, June 21

FLEXIN' on Fathers Day... #HappyFathersDay to ALL of the Dads out there from the newest member of the Daddy Fraternity!! --JT

A photo posted by Justin Timberlake (@justintimberlake) on Jun 21, 2015 at 9:11am PDT

Look at that little tush! Justin Timberlake is loving his first Father's Day so far. The "Mirrors" singer proudly shared a new photo of his son Silas via Instagram and Facebook on Sunday, June 21, in honor of the special day.

"FLEXIN' on Fathers Day…" Timberlake, 34, captioned. "#HappyFathersDay to ALL of the Dads out there from the newest member of the Daddy Fraternity!!"

In the snapshot, the new dad is looking oh-so-cool while holding his 2-month-old baby boy. Silas' face is turned away, but his embroidered "I Love Dad" note on his blue onesie is cute enough!

Us Weekly broke news in April that Timberlake and wife Jessica Biel welcomed their first child together. On April 19, their newborn made his Instagram debut!

The Timberlakes are ready!!! GO GRIZZ! #GritNGrind #Playoffs #BabyGrizzROAR

A photo posted by Justin Timberlake (@justintimberlake) on Apr 19, 2015 at 5:12pm PDT

"The Timberlakes are ready!!! GO GRIZZ! #GritNGrind #Playoffs #BabyGrizzROAR," Timberlake captioned a pic, while watching a Memphis Grizzlies basketball game. The new mom, 33, looked elated while holding their little one. 

"Jessica sees herself as a mom of boys, so it worked out perfectly," an insider previously told Us. "Justin is so excited, he doesn't know what to do with himself!"

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