Julia Roberts was avoiding the question. Dressed casually in jeans, a pastel green T-shirt and vintage jacket, America's star of stars faced a room of about 45 reporters at Manhattan's Regency Hotel June 23 to promote her forthcoming movie America's Sweethearts. The reporters, naturally, were more interested in her and her sweetheart, the former star of TV's Law & Order Benjamin Bratt . But when one asked, fatuously, what made the couple's life together "so happy and wonderful," Roberts rambled on about how Bratt had taught her to "take comfort in my privacy." The reporter persisted: "But is there one quality you admire about each other that makes it special?" Responded Roberts: "I would say mutual respect and integrity."

"See, that wasn't so hard," teased her interrogator.

"Well, yeah," Roberts shot back, "your stomach doesn't hurt."

The bellyful of butterflies was a symptom of Roberts's big secret: A month earlier the 33-year-old Oscar winner had quietly parted ways with Bratt, 37, ending a nearly four-year relationship. Theirs had been a public romance, played out in kisses and cuddles and gushing speeches at awards ceremonies, including March's Screen Actors Guild Awards, where Roberts-collecting the sixth of eight statuettes for her role in Erin Brockovich -- invited reporters to "come to our house. We're happy all the time!" The pair had decided to make no public statement about their split, but eventually the news was leaked to the New York City tabloids on June 28, surprising both fans -- who had been on a wedding watch for months -- and friends. "They were extremely loving," says movie producer Howard Rosenman, a longtime friend of Roberts's. "They were into each other's heads and souls. They were supportive of each other. They looked like they were in love."

And they didn't hide it. As recently as May, Bratt and Roberts were seen smooching over sandwiches at a Manhattan cafe, window-shopping hand in hand in Greenwich Village and strolling down St. Mark's Place, making a giddy game of eating watermelon. "They were spitting out the pits to see who could spit the farthest," says a witness. But by then the seeds of discontent had well and truly taken root. Soon afterward Bratt returned to Montreal, where he had been filming the psychological thriller Abandon since April. In late May and in June, Roberts visited the set more than once to try and save the relationship by spending time with him. But in the end "it wasn't enough," a source says of the couple. "They couldn't be the person the other one wanted them to be."