Ronald Harwood has adapted his own play about retired opera singers putting on one more show for the retirement home that is their special last refuge. Dustin Hoffman, making his directorial debut, amiably indulges a frisky cast of veteran Brit actors. The arrival of haughty diva Jean Horton (Maggie Smith) makes possible an on-stage reunion of the eponymous quartet, but maybe not—Horton’s still-heartbroken ex-husband (Tom Courtenay) figures in the erstwhile quartet and the now-humbled diva has her own pride and self-doubt to deal with. The other members, the exuberantly randy Wilf Bond (Billy Connolly) and the sweetly erratic Cissy Robson (Pauline Collins), nudge things toward geriatric farce early on. But once the diva is present, the tone changes to something verging on the tragicomic, and the feel-good finish (with a decorous touch or two of the bittersweet) is certain to draw a few well-earned tears. Pageant Theatre and Paradise Cinema 7. Rated PG-13.