( CM ) - CELINE DION has been giving BETTE MIDLER tips on how to protect her voice as the singer/actress prepares to start a 30-month residency in the desert. Dion ended her five-year performance stint at Las Vegas' Caesar's Palace Colosseum venue in December (07), and now she's coaching her successor, Midler, on how to cope with the fierce desert heat. Midler says, "She gave me all her doctors' phone numbers. She said, 'Don't talk during the day,' and told me, 'Beware of the wind.' "She had humidification built under the stage and into this dressing room. She cranked it. It was like the Amazon in here, and I intend to keep it the same. "We've got vapourisers everywhere." Midler begins her Las Vegas residency later this month.