Rob Lowe rings in his milestone 60th birthday with Katy Perry, Robert Downey Jr., Cameron Diaz, and more at extravagant Santa Barbara bash

Rob Lowe celebrated his 60th birthday with a star-studded soirée in Santa Barbara on Saturday, wearing a sleek black pinstripe suit.

The producer-host of Floor — who technically reached the milestone on March 17 — invited family and A-list friends, like American Idol judge Katy Perry and her fiancé Orlando Bloom.

Newly minted Oscar winner Robert Downey Jr. arrived wearing sunglasses and an all gray suit.

Four-time Golden Globe nominee Cameron Diaz — who is in the midst of a Hollywood comeback — held a branch of flowers next to her husband Benji Madden, with whom she just welcomed her second child (son Cardinal) via surrogate.

Rob’s 28-year-old son John Owen Lowe Installed a photo of the large sign that greeted guests at the bash that read: “No photos allowed on social media.”

Lowe’s party was also attended by Zoe Saldaña, Amy Poehler, Kevin Costner, Jennifer Aniston, Gwyneth Paltrow and husband Brad Falchuck, Ellen DeGeneres and wife Portia de Rossi, Adam Levine and wife Behati Prinsloo, Chris Pratt and wife Katherine Schwarzenegger, Christopher Schwarzenegger, and Maria Shriver.

The Brat Packer hired a live band featuring Grammy-winning jazz saxophonist Kenny G to entertain the crowd until 1:30 am.

The Floor producer-host — who technically reached the milestone on March 17 — invited family and A-list friends, like American Idol judge Katy Perry and her fiancé Orlando Bloom

Newly minted Oscar winner Robert Downey Jr. arrived wearing sunglasses and an all gray suit

Four-time Golden Globe nominee Cameron Diaz – who is in the midst of a Hollywood comeback – held a branch of flowers next to her husband Benji Madden, with whom she just welcomed her second child (son Cardinal) via surrogate

Rob’s 28-year-old son, John Owen Lowe, posted a photo of the large sign greeting guests at the party: “No photos will be posted on social media.”