The job — a career breakthrough — is supposed to go to hoofer Johnny Brett, but a mix-up in names gives it to his partner. Another example of Broadway hopes dashed? Not when Johnny is played by Fred Astaire. Sparkling Cole Porter songs, clever comedy and dance legends Astaire and Eleanor Powell make the final Broadway Melody (costarring George Murphy) a film to remember. Powell’s nautical “I Am the Captain” and Astaire’s blissful “I’ve Got My Eyes on You” are more than enough to please any fan. But they’re just a warm-up for the leads to tap one number into immortality: “Begin the Beguine,” introduced by Frank Sinatra in That’s Entertainment! with, “You can wait around and hope, but you’ll never see the likes of this again.”