The two surviving Beatles, Paul McCartney and Ringo Starr, have made a rare joint appearance at the world premiere for a documentary film of last year’s concert tribute to their late colleague, George Harrison.McCartney and Starr, accompanied by their wives, Heather Mills and Barbara Bach, arrived separately at the Wednesday event but spoke briefly and posed together for pictures on the Warner Bros Studios lot in Burbank, California. The movie, Concert for George, captures the all-star concert staged last November at London’s Royal Albert Hall celebrating the life and music of Harrison a year after he died of cancer at 58.