Rob Lowe's Son Matthew Marries Emily Markus in Star-Studded Wedding

Rob Lowe's eldest son, Matthew Lowe, tied the knot with Emily Markus in a star-studded California wedding ... with Gwyneth Paltrow taking on a very special role in the ceremony.

The couple said "I do" Saturday at the Rosewood Miramar in Montecito, California, surrounded by some of Hollywood's biggest names ... including Katy Perry, Cameron Diaz, Chris Pratt, Zoe Saldaña, Adam Levine, Behati Prinsloo and Maria Shriver.

But the celebrity guest list wasn't the only thing making this wedding special ... Gwyneth actually officiated the ceremony, which Page Six was the first to report on, bringing things full circle with her longtime pal Rob.

Gwyneth and Rob have been friends for decades, so having the "Shakespeare in Love" star help usher his son into married life was a pretty special moment for the family.

Matthew is Rob's eldest son with wife Sheryl Lowe. The couple also share a younger son, John Owen, who was on hand to celebrate his big brother's milestone.

Matthew and Emily got engaged in July 2025, with Matthew sharing romantic photos from the proposal on social media and jokingly captioning the post "Lord of the rings."

The wedding comes during an especially emotional time for the Lowe family. As we previously reported, Rob's niece, Fiona -- the 13-year-old daughter of his brother Chad Lowe -- recently died.

The family has publicly expressed its heartbreak and asked for privacy as they grieve. Chad, Kim, and their surviving daughters were also photographed at the wedding ... marking their first public appearance since Fiona's death,.

Despite the family's recent heartbreak, loved ones gathered to celebrate Matthew and Emily as they began their life together.

Rob has previously talked about looking forward to becoming a grandfather, although he's admitted he's not quite ready for the title just yet.