Here's the finale from Paramount's Variety Girl, the last of the all-star studio revues where the studio's contract players gather together for a good cause. Most of these films were made during the war, but this is from 1947, and the good cause this time was the charity organization Variety Clubs International.
Almost every Paramount star except Betty Hutton is in this film. In the finale, Bob Hope and Bing Crosby sing "Harmony" by Crosby's regular songwriting team, Jimmy Van Heusen and Johnny Burke, and then the other stars all come on to sing a bit of it. I would suggest that you try to identify which stars are in this picture, but the person who uploaded this has put in the opening credits, where most of the stars are identified with caricatures by T. Hee.
By the way, the same person has uploaded another bit from Variety Girl, a scene with Burt Lancaster, William Demarest and Lizabeth Scott that may have the unfunniest punchline in history.