Rob Lowe’s Son John Turns 21 — See How the Family Celebrated His Milestone Birthday!

That looked fun!

Rob Lowe's son John turned 21-years-old on Sunday, Nov. 6 — and the family celebrated his milestone birthday by taking a memorable trip to Las Vegas over the weekend!

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#birthday #vegas 21 and done!!

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"#Birthday #Vegas 21 and done!!" the Brothers & Sisters star captioned the snapshot of himself, his wife, Sheryl Berkoff, John and the couple's older son, Matthew, 23, at a club. Who says you can't party with your parents?!

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Rob and Sheryl — who married in 1991 — previously welcomed John in 1995 and Matthew in 1993.

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