There is always a danger with the title of your film - another movie might use some part of it and you'll get them confused if they come out at the same time (A Late Quartet and Quartet). It's almost as bad as two movies with the same story coming out at the same time (Mirror, Mirror and Snow White and the Huntsman). It's nearly inevitable that one will fail in comparison. I feel I can safely say it is NOT going to be Quartet that fails, and you should get your butt to the theater immediately and see this.
Quartet is directed by Dustin Hoffman, and there are moments of his whimsical sense of humor throughout, though subtle. The movie follows former opera singers and musicians at their retirement home, specifically Wilf (Billy Connelly), Cissy (Pauline Collins), and Reggie (Tom Courtney). They once performed together in Rigoletto. Now they relive their dreams and try to stay coherent as they decline in health, but often get to practice and live their diva-natures to the fullest. They're getting ready for a benefit to save their home directed by super diva Cedric (pronounced "see-dric", Michael Gambon in a house dress). A new resident arrives and throws everything off, an uber famous soprano Jean (Maggie Smith), but eventually she agrees to help - she was the fourth in the Rigoletto quartet with our three heroes and now their reunited.
This movie has a simple premise - once a diva, always a diva. And put all of them into a house together living out their golden years and a lot humor and heart will result. It's true - I loved this movie. There is a lot of great music, lots of snide British comments, a love story, past wrongs righted, and so much heart yours will nearly burst. I won't give you more examples, and just urge you, and everyone you know to see this as soon as possible.