Fresh off his Rookie of the Year award, Dallas Mavericks Cooper Flagg made things Instagram official with girlfriend, Duke women’s basketball center Ari Roberson, on Thursday.

The rumors are true. Dallas Mavericks rookie Cooper Flagg is in a relationship with Duke University center Arianna Roberson.

In early May 2026, the two basketball players fueled heavy speculation by posting separate, nearly identical photos from Noah's Ark Beach Club in Turks and Caicos on the very same day.