"Grey's Anatomy" is back tonight after quite a season finale! Cristina (SANDRA OH) was left at the altar. Meredith (ELLEN POMPEO) and McDreamy (PATRICK DEMPSEY) broke up, and George (T.R. KNIGHT) found out he failed his intern exams.

"He's repeating his intern year," T.R. tells ET's JANN CARL on the set of the hit medical series. "His options were to walk away, or to repeat it, so, he's a repeater. He's made a lot of mistakes and that was one of them. You know the adultery and all that, so he needs to work out some stuff."

And part of working out that stuff means he has to figure out whether he wants to stay married to Callie (SARA RAMIREZ), or pursue his budding relationship with Izzie (KATHERINE HEIGL).

While neither T.R. nor Katherine would reveal the future of "Gizzie," they did talk about their romantic kissing scene -- not!

"When we were kissing, I was chewing that gum," T.R. recalls.

"They have this apple gum on the camera cart," Katherine explains. "It's apple flavored, but, literally, to me, it smells like vomit. It smells like that taste in your mouth before you are going to throw up. So, the fact that I had to kiss him, and he had that gum in his mouth, was really throwing me off, because I was thinking of throwing up."

The season premiere of "Grey's Anatomy," airing tonight at 9 p.m. on ABC, is different this year, because, with the exception of George, the rest of the gang -- Meredith, Cristina, Izzie and Alex (JUSTIN CHAMBERS) -- are now surgical residents.

"We have just a tiny modicum of power now, but not like Bailey (CHANDRA WILSON) and not like Callie who is the chief resident. We have our own interns now -- a new group of young, eager students, so they are basically who we were two years ago," Katherine shares.