Credit: Karwai Tang/

Duchess Cressida? Prince Harry was on royal business at London's Wembley Arena on Friday, March 7 to host the first-ever UK We Day, where he joined 12,000 10-18 local kids for a global youth empowerment event. On hand to support the redheaded royal, 28: Princess Beatrice and boyfriend Dave Clark; Richard Branson and his family; Jennifer Hudson, Al Gore, Ellie Goulding . . . and Cressida Bonas. See the latest pics of Cressida here.

Although the fun-loving model, 24, has been dating Harry since June 2012, Friday's event (which was organized by Free the Children) marked the first time she attended any of his official royal events -- the strongest signal yet that the couple are serious about one another. Following Harry's remarks to the crowd, he joined his love in the stands, where they were photographed huddling together. Showing off a markedly different style than, say, Kate Middleton, Bonas wore sneakers, leggings and a leather biker jacket for the event.

Prince William's little brother, whose prior relationship was with on-and-off love Chelsea Davy, was introduced to Bonas via his cousin Princess Eugenie, a lifelong pal of Bonas. "He loves her -- they're so compatible," a source told Us Weekly late fall. "Cressie is very laid-back and he likes that. If all goes well, I'm 100 percent sure they'll be engaged next year."

A graduate of Leeds University and the Laban Conservatoire of Music and Dance, Bonas is the daughter of banking heiress Lady Mary-Gaye Georgiana Lorna Curzon and entrepreneur Jeffrey Bonas.