As we reported last week, the final scene in Grey's Anatomy's fifth season finale was supposed to feature Jeffrey Dean Morgan's Denny Duquette, who was seen throughout the season, as Izzie's heavenly escort as the ailing resident's life hung in the balance.

However, series creator and executive Shonda Rhimes had an epiphany and decided to use T.R. Knight's George O'Malley in the parting shot-cliffhanger instead

According to Entertainment Weekly, having wrapped filming for the season, T.R. Knight went ahead and shaved his head, believing he was done for the summer.

That posed a new problem - but ultimately a solution - for Rhimes.

"[Director] Rob Corn calls me up and goes, 'What do we do?'" Rhimes said, before she remembered George enlisted in the Army right before being struck by a bus.

Luckily, the workaround quickly came to Rhimes when she thought of that fact. "I said, 'I know. Put him in a military uniform!' It wasn't a big amazing plan I had."

The climactic, season-ending scene, which left the two characters literally in limbo and viewers on the edge of their seats, left Knight with a bag of emotions as well.

"It was brilliant of Shonda to put George in the dress blues," said Knight, who will not be returning to Grey's Anatomy next season. "It was such a powerful image."

Katherine Heigl, who plays Izzie, was in Atlanta shooting a film and was not present for the big re-shoot. So to ensure Heigl and Knight's expressions were in sync, T.R. Knight picked his BFF's brain over the phone before stepping in front of the camera.

"I was like, 'What did you do in that scene?'" the Grey's Anatomy actor said, laughing. "It's nice when you've worked with someone for five years. There's a shorthand."

Katherine Heigl was worried over whether the switcheroo could be pulled off.

"Katie called me and was like, 'Are my expressions going to match his? Is it going to work?" Rhimes said. "And I was like, 'I promise you it's going to be perfect.'"

It was.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.