At the American Film Institute's 40th Life Achievement Award Ceremony honoring Shirley Maclaine, broadcast on the TV Land channel on Sunday, June 24, Katherine took to the stage to speak of her admiration for the screen legend, treating the audience to her impression of one of the actress's most beloved characters.

Katherine Heigl At The American Film Institute's 40th Life Achievement Award Ceremony

"I've spent the last 21 years trying to perfect your zingers from Steel Magnolias," Katherine explained, referring to Maclaines character Ouiser Boudreaux and mimicking her famous line from the film, "I'm not crazy, I've just been in a very bad mood 40 years!"

Check out the video clip of Katherine's speech from the gala event which took place on June 7 at Sony Pictures Studios in Los Angeles.