Answering Hollywood casting calls:

Jazz legend Miles Davis has signed to make his acting debut in "Dingo," about a young boy who is mesmerized by a musician he tries to emulate . . . Julia Roberts has agreed to star in "Dying Young," playing a young blue-collar woman hired to care for a rich New Englander dying of leukemia.Engelbert Humperdinck will headline the syndicated mini-series "Sherlock Holmes and the Leading Lady," due to air later this season. . .. Harrison Ford and Annette Bening have begun filming "Regarding Henry" in New York, with Mike Nichols directing.

Robin Williams and Dustin Hoffman have signed to work together on "Hoo," described as a "Peter Pan for the 1990s." Filming is due to start in January . . . . Loren Dean has the title role in "Billy Bathgate," based on the E.L. Doctorow novel.

Buddy Hackett, Hayley Mills, Robert Morley and Cloris Leachman have joined the voiceover cast of the animated "A Troll in Central Park," due for release next spring.

Danny DeVito is set to star in director Norman Jewison's version of "Other People's Money," the off-Broadway play about high finance, greed and romance . . . . Bruce Willis has signed to star in "Three Rivers," a police suspense story with a reported $40 million budget.

Diane Keaton makes her debut as a primetime TV director in a "China Beach" episode due to air later this season on ABC-TV . . . . Demi Moore and Jeff Daniels begin filming "The Butcher's Wife" next month in North Carolina.