GOOD MORNING: Will Charles and Di show up together at the Royal preem of “Far and Away” on July 30 at London’s Empire theater in Leicester Square? That’s what producer Brian Grazer asked us after he’d been one of the 26,000 visitors–including us–at the “Backdraft” attraction on Universal Hollywood’s tour. “They (the Royal couple) attended the ‘Backdraft’ Royal premiere together, ” he recalled. But that was before the Royal fireworks. Tom Cruise, Nicole Kidman, Tom Pollock and Ron Howard are to be at the preem with Grazer and his lady, TV exec Gigi LaVang The latter, along with producer Grazer; his two children, Page and Riley; and yours truly braved the 106-degree outside temp at Universal City and the 120-degree heat (he said) in the “Backdraft” experience, which Grazer claimed was as lifelike as the actual shoot in Chicago. Audiences are apparently agreeing–Sid Sheinberg told Grazer that attendance at the U Studio tour has risen 20% since “Backdraft” bowed earlier this month on the tour. Ron Howard, Scott Glenn and Kurt Russell filmed a special intro piece visitors see before they enter the conflagration. “I don’t know how they (the tour’s creators) did it,” said Grazer–echoing moviegoers’ wondering how he made the movie. … Steven Spielberg would be happy to know that Grazer said he went on the “E.T.” ride five times (with his kids). Steven was also a tour visitor last week with his children. … Grazer, having wound “Cop and a Half” and enjoying the box office returns on “Boomerang” (close to $50 million) and “HouseSitter” ($47 million), left last night with LaVang for a vacation at the Villa d’Este in Lake Como before heading to the Royal preem in London. Next on his (and Ron Howard’s) sked is “Cowboy Way” at Universal with Woody Harrelson. A resolution of the Imagine-Grazer-Howard-Universal deal is being finalized, he says, and he’s prepping to start other films, among ‘em “Curious George.” … Universal’s Studio tour continues its expansion with a planned fall opening of its City Walk mall to carbon Westwood Boulevard, Melrose Avenue, etc. , and will also include room for UCLA extension classes. A six-day celebration, “Halloween Haunt,” will also lure off-season visitors there. And next summer, it’s an enormous “Back to the Future” ride.FIRST IT WAS Melanie Griffith and director Sidney Lumet (in “A Stranger Among Us”) and now Melanie’s husband Don Johnson will toil for/with Lumet in producer Martin Ransohoff’s “Beyond Innocence” at Hollywood Pictures. The script’s by Larry Cohen. Johnson tells us it’s the most interesting script he’s read in a long time–he plays a heavy with “a very strange occupation” in the murder mystery. Rebecca de Mornay co-stars as the attorney. Johnson is, of course, now playing opposite wife Melanie in another, most interesting role as the magazine writer in “Born Yesterday,” a role originated on-screen by William Holden “Born Yesterday’s” exec producer, Stratton Leopold, is currently also working on winding another Hollywood picture while in production on “B.Y.” It’s the Taylor Hackford “Blood In, Blood Out,” which has been undergoing some bloodletting to cut it down from its over-three-hour length. And Leopold says they must shoot a change in the ending of the realistic film, set in East L.A. But Leopold claims it’s Hackford’s finest movie. … Lisa Brok-Linson, location manager on “Born Yesterday,” suffered a double fracture to her right foot when she was struck by a car while she was in a crosswalk (with a traffic light in her favor) on the company’s location at restaurant Rex last Friday p.m. Brok-Linson has filmed around the world, and her first mishap was right here in L.A. She and husband, editor (“Indian Runner”) Phillip Linson, are readying to produce a feature on their own. NOT ON THE BILL: Trish Van Devere and Martin Sheen have been performing “Love Letters” and getting raves in Santa Barbara. After Sheen appeared with Van Devere in the Sunday matinee–George C. Scott took it on himself to replace Sheen in the evening show and joined wife Trish in the romantic two-character play. Ain’t love grand. Scott is readying to star in David Permut’s “Buddy Cops” at Disney, will also narrate the IMAX movie about the Kuwait firefighters. And Scott’s also the voice for Smith Barney commercials. … Merv Griffin’s reassembling his 21-piece orch, plus the Merv-Tones, for the “Wheel of Fortune” 10th anni bash July 30 at the BevHilton (natch). Merv and the group just played to big biz and mucho dancing at his Resorts Intl. in A.C. Add nostalgia note: Among those catching the mellow tones of “Forever Plaid” at the Canon, Mel Torme (remember his MelTones?), Dinah Shore, Rosie Clooney, Jerry Vale, Gogi Grant, Ed Ames, Patti Page, Sandler & Young and the Four Preps. … John Gaines has opened his own agency. He met with Michael Eisner and Jeffrey Katzenberg at Morton’s last evening. … John Hurt has signed with the William Morris agency, continues with John Crosby management . … Michael Nathanson, Columbia Pictures prez of worldwide production, and wife Diana welcomed their first, daughter Olivia Victoria N., July 18 at Santa Monica hospital. … Earl Wingard’s wife of 52 years, La Verne, died yesterday. … And Jack Hirshberg’s wife of 43 years, Lois, died July 8. … Today’s “Arsenio Hall Day” as he donates the “Unity Hall” youth facility to the A.M.E. Church.