The ever-smiling Meg Ryan looked luminous at a party Sunday night for her new film "Kate & Leopold," opening this week. The party was held in the grand main room of the enormous New York restaurant Guastavino's, located in the vaulted anchorage under the Manhattan Bridge. Her costar is Hugh Jackman, 33, who is best known, so far, for his performance as the sexy beast Wolverine in last year's "X-Men." In "Kate & Leopold," Jackman plays a 19th-century duke who travels in time to present-day New York, where he meets and woos a too-busy-for-love marketing exec (Ryan). Director James Mangold ("Girl, Interrupted," "Heavy"), who was celebrating his 38th birthday that night, said of the film: "In many ways, this is a love letter to this great romantic city." He went on to say Jackman's character is more than a syrupy romance-novel fantasy. "This is not a movie about manners," says Mangold. "It's a movie about grace. Just like chivalry is not just about etiquette or what fork to hold in which hand. It's about looking someone in the eye and being direct and honest."