MONTREAL — Canadian pop star Celine Dion has booked a last-minute berth on “Titanic,” the much-anticipated James Cameron pic, and she’ll be belting out the film’s theme song, “My Heart Will Go On.”Penned by James Horner, the shipwreck ballad was produced by Horner and seasoned knob-twirler Walter Afanasieff. Don’t expect to see the Montreal chanteuse’s career sinking to the bottom of the pop sea any time soon, however. Her previous album, “Falling into You,” has sold a seaworthy 25 million units around the globe, and her upcoming 550 Records release looks to be another chart-topper. Newly retitled “Let’s Talk About Love” (and not “The Reason,” as previously announced), the disc, due in North American stores Nov. 18, contains a number of high-profile duets, including “Never, Never, Never” with tenor Luciano Pavarotti, and “Immortality” with the Bee Gees. Another track, “The Reason,” was penned by Carole King and features her on piano and vocals. But the real dynamic duo teams balladeer Dion with the genre’s ace practitioner, Barbra Streisand. Their duet, “Tell Him,” was penned by frequent Dion collaborator and fellow Canuck David Foster, and is due on radio Oct. 8. In an unusual move, it is the first single from both the new Dion album and the upcoming Columbia Streisand album, “Higher Ground,” and will be included on both records.