U.S. cable network HBO says it plans to air "James Gandolfini: Tribute to a Friend" Sunday. The half-hour program will feature appearances by the late New Jersey actor's friends and colleagues, as well as clips from his TV and film projects, Deadline.com reported. Gandolfini died of a heart attack June 19 in Rome at age 51. He won three Emmy Awards for his portrayal of mob boss Tony Soprano in "The Sopranos," a show that ran for six seasons from 1999 to 2007 on HBO. Gandolfini was posthumously nominated for a Screen Actors Guild Award last week for his performance in the movie "Enough Said."