These days, wherever Katie Holmes goes – press conferences for Batman Begins, TV interviews and autograph sessions – Jessica Rodriguez is never far behind, PEOPLE reports in its latest issue.

“They’re always together,” says one source. Since Holmes met Rodriguez – soon after the star began dating Tom Cruise in April – “they’ve become good friends. They go shopping, they go out.”

And they’ve been generating headlines. Why all the fuss? Because Rodriguez is employed by the Church of Scientology, Cruise’s controversial religion. And though a source close to Holmes says that Rodriguez is traveling as a friend and assistant – not as a religious adviser – the blossoming friendship indicates that Holmes is getting more serious about Cruise, 42, and more deeply involved in Scientology.

One source says Holmes, 26, is “now a Scientologist.” Holmes herself has only said she’s taking lessons. “I’m really excited about (Scientology),” she told reporters in London June 12. “I know how important it is to Tom, and I want to be able to share that with him.” (Holmes, who hails from Ohio, was raised Catholic; a Scientology rep says Scientologists need not renounce their faiths to join.)

It’s not the only way life has precipitously changed for the former Dawson’s Creek star. “Since meeting Tom, she hasn’t spoken to any of the people she used to hang out with,” says one source. Though to be fair, Holmes hasn’t had much time to chat lately, between a busy promotion schedule for Batman Begins and jaunts with her new man.

Holmes has also made career changes recently. She dropped her manager and changed reps at the Creative Artists Agency. She also turned down the role of drug-addicted Andy Warhol acolyte Edie Sedgwick in the upcoming movie Factory Girl. A source claims she did so because Cruise thought she shouldn’t play a victim – though a friend of Holmes’s (who calls her “Kate”) says that “Kate’s decisions in terms of her career are Kate’s decisions. Tom has done nothing but support her.”

Some friends and coworkers aren’t worried about Holmes. “She’s centered and smart, and she has an amazing backup system with her family,” says Dawson’s Creek executive producer Paul Stupin. “If she is letting (Cruise) into her life, she’s a great judge of people, and I’m sure she s doing the right thing.”

A more concerned friend feels Holmes is understandably swept up in the moment. “You have to remember, she’s a young girl and this is Tom Cruise,” says the friend. “I would have jumped off a bridge with Tom Cruise at 26.”

As for Holmes, she freely admits she has fallen. At the Paris premiere of Batman Begins June 14, she said, “I don’t care what people think, and I’m very, very happy.”