With her blonde British sweetness, Juliet Mills has had a less widespread profile in the US than her Oscar-winning father Sir John Mills or her more famous child actress sister, Hayley. But found some fame as Phoebe Figalilly, the Mary Poppins-esque caretaker in the gentle sitcom "Nanny and the Professor" (ABC, 1970-71) and earned much space in the gossip columns when she married actor Maxwell Caulfield, 18 years her junior, in 1980.Mills made her screen debut at age 11 weeks in her godfather Noel Coward's acclaimed war picture, "In Which We Serve" (1941). She then appeared alongside her