Sylvester Stallone isn't the only knockout in his family!

The Rocky star posed two of his daughters Sophia, 19, and Sistine, 17, in an Instagram snapshot on Thursday, May 12 — and the sisters are so grown up and gorgeous!

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Growing up fast!

A post shared by Sly Stallone (@officialslystallone) on

"Growing up fast!" the 69-year-old actor captioned the sweet photo of the three all dressed up.

RELATED: Sylvester Stallone Shares a Fun Selfie With Daughters Sistine and Scarlet — See the Pic!

Sylvester and his wife, Jennifer Flavin — who tied the knot in 1997 — are also parents to a younger daughter Scarlet, 13. The actor is additionally a father to sons Seargeoh Stallone, 37, and Sage Stallone (who sadly died from a heart disease in 2012 at age 36) with his first wife, Sasha Czack.

Click through the gallery below to more celebrity kids all grown up!