PHOTOSKate Middleton Steps Out With Prince William and Prince Harry to Launch New Charity Campaign

Looking' good, Kate Middleton!

The 34-year-old royal stepped out with her husband, Prince William, 33, and brother-in-law, Prince Harry, 31, on Monday, May 16 to attend the London launch of their new charity campaign, Heads Together.

Click through the gallery to see more photos of the stylish trio at their Heads Together event!