Princess Diana's dance partner, Wayne Sleep, was one of the late royal's most trusted friends after their friendship blossomed during dance rehearsals. The pair got to know each other after Diana contacted him to coach her for a surprise performance at London's Royal Opera House back in December 1985.Several weeks ahead of the event - Friends of Covent Garden - the two friends secretly choreographed a dance to Billy Joel's Uptown Girl as a birthday present to Prince Charles.