Nicole Kidman's summer "romance" with Michael Reinstein is revving up, sources said, even though she won't confirm it.

Breaking Celebrity News can reveal the Oscar winner was spotted getting cozy with Reinstein, founder of a Beverly Hills-based investment firm, in Italy in July – and he was Johnny-on-the-spot when she jetted into L.A. on July 30 after the season premiere of her series Lioness.

"Michael was waiting at the airport in his Ferrari when Nicole flew in from New York City. Obviously, this was more than just a little holiday fling," said a source.

"Still, Nicole is refusing to label it. When people ask, all she'll say is that she's having fun, but Michael is pursuing her very hard and she seems to be very charmed.

"But Nicole is not ready to say it's anything serious or completely allow herself to fall for him. She wants to take things slowly and build on what they have to make sure it's genuinely a good thing for her."

Since her divorce from Keith Urban was finalized earlier this year, the Big Little Lies star has focused on spending time with their daughters, Sunday Rose, 18, and Faith Margaret, 15.

Kidman, 59, has also traveled widely, bouncing from Chile to Antarctica to Paris to Italy, where she vacationed with her sister, Antonia.

As for romance, insiders said before she was seen with Reinstein, Kidman was pursued by Paul Salem, a private equity investor and chairman of the board of MGM Resorts International.

But insiders said Kidman is far from desperate to land a man.