According to E!'s Kristin Dos Santos, Susan was spotted at Warner Bros. Studios in Burbank last week filming scenes for the finale.
So far the plot line has been kept under wraps, but sources on set did spill the beans about working with George.
"He was charming," one ER crewmember told E! "Everyone had a great time with George, and he told some great stories about the old days. He really enjoyed himself and was glad he did it."
What do you think of Susan joining the cast? Who else would you want to see make a cameo in the season finale? Maybe Britney can make a cameo on a gurney. Now that's what we call entertainment!