By Kat Giantis

She sings peppy ditties about kissing girls and has a predilection for dressing up as potassium-rich fruit; he emotes onstage with a booming baritone that makes women of a certain age inexplicably weak in the knees.

But are Katy Perry and Josh Groban a match made in pop music heaven?

That's the word from Perez Hilton, who says the calculatingly quirky singer and the curly-locked balladeer are quietly dating.

"They've been trying to keep it very low profile," tattles a spy.

Perhaps the purported pairing was helped along by Perry's recent admission that she harbors a secret soft spot for the squeaky-clean crooner.

"Who's my most embarrassing crush?" she was quoted as musing. "I suppose it would have to be Josh Groban. He is actually really cute!"

Katy, 24, split with Gym Class Heroes front man Travis McCoy in early January and joked soon after that she'd taken a vow of celibacy for the year (she later clarified that she'd "rather die" than give up nookie).

Last month, she denied reports that she'd hooked up with Paris Hilton cast-off Benji Madden.

Groban, 28, has reportedly been flying solo since calling it quits with "Mad Men" actress January Jones in 2006 after three years of togetherness.

Meanwhile, on the other end of the romance spectrum, that strange whimpering sound you hear? It's a million frustrated "Transformers" fanboys upset with how the rumor mill continues to toy with their emotions over Megan Fox's status with Brian Austin Green.

The fame-mismatched flames, who were hit with breakup chatter a few weeks back, are supposedly on the outs yet again.

E! News claims the tumescent-lipped, ink-stained starlet, who has been engaged to the actor for two-plus years and just enjoyed a bronzing session a deux with him, left his Hollywood Hills home over the weekend and checked into a hotel.

Observes an insider of Fox's ostensible relocation, "Well, when someone leaves and goes to a hotel, it doesn't exactly say, 'Let's get married,' does it?"

Next: Lindsay's credit crunch