Will Katherine Heigl Return to Grey's? Justin Chambers Answers, and Reveals Alex's Mushy Secret

It's here! Tonight's Grey's Anatomy is the one you Justin Chambers/Alex fans have been waiting for: We finally get to find out something about his character's past—and, according to Justin, "what makes him tick."

[And, oh yeah, as you can see below, he will be all lathered up, wet and nekkid--not that you would care at all about that.]

I just hit the Grey's set, where Justin was shooting a May sweeps episode with Demi Lovato (for now those details are super hush-hush), and Seattle Grace's resident bad boy dished on tonight's episode, his recent sexcapades with Lexie (Chyler Leigh) and why you should never count out Katherine Heigl…

"Never underestimate Katherine Heigl," Justin tells us. "She'll probably [be back]. I miss her immensely." So does that mean Alex and Izzie might somehow live on? "I think he'll always have a soft spot for Izzie and he's going to miss her very much. Who knows, anything's possible on Grey's Anatomy, she might be back."

Still, as you can see in the sneak peek of tonight's episode, Izzie's serving Alex with divorce papers.

Time to move on. So Alex is having a fun little fling with "Little Grey," aka Chyler Leigh, aka the girl who just broke up with Mark Sloane (Eric Dane), much to the devastation to some of you fans.

"I hope Alex finds love. It just seems like whenever he does, he doesn't know how to deal with it," Justin tells me. "It's a little physical [with Lexie]. It's kind of a rebound. Alex married Izzie and said all those wonderful things and I don't think you can just fall out of a relationship that easy. It's a bit of a rebound, but she's a cute girl. She's a sweet girl…and blond now. So maybe there's something there," he laughs.

Tonight, Alex's brother shows up at Seattle Grace and, from the looks of the sneak peek above (and the promo where they come to blows), there's some bad blood. "We're getting into some of Alex's backstory," Justin teases. "It's been six seasons and we haven't met anyone from his family. His brother comes to town for some issues and more issues arise. It's good stuff...We had Debbie Allen direct the episode, which was a real honor, so I think it turned out pretty well."

Oh yeah, and Alex Karev's biggest secret? It's a mushy-gushy-gooey one you might want to sandwich between a graham cracker...

"He's a marshmallow underneath it," Justin says. "He's got a lot of bravado behind his mouth, but we're starting to see a more sensitive side to him."

Watch out, Sloane. There may be a future for Alex and Lexie after all.

Which couple are you rooting for on Grey's? Is Lexie a better match for Marshmallow, McSteamy or none of the above?