Miley Cyrus romance with Patrick Schwarzenegger ramps up

What started as a pretty casual flirtation seems to be getting more and more serious. I’m hearing that Miley Cyrus’ romance with Patrick Schwarzenegger — the model/actor son of Kennedy heiress and broadcasting veteran Maria Shriver and ex-California governor and action star Arnold Schwarzenegger — has moved into high gear. The two 21-year-olds are said to be totally taken with each other.

What’s amusing to some longtime, close Cyrus insiders is the impact this budding relationship seems to be having on the pop superstar. “Whenever Miley knows she’s going to something serious, like with Patrick’s mom or other family members, she dresses so totally different from her usual outfits. … It’s like she’s bought a whole Jackie Kennedy-like wardrobe for those occasions,” said a Cyrus source on Saturday.

“Actually, it’s good. She’s looking more like a grown-up now,” added the Miley pal.

As for Shriver, I hear she’s taking it all in stride. “I don’t think Maria is the least bit worried. I think she sees it simply as a situation where Patrick is dating someone cute, who just happens to be extremely famous. They both understand the celebrity thing. … But Maria and Arnold both know Patrick is only 21. … This will likely not last,” a longtime friend of the Shriver family told me early Sunday.