Mom of three Katherine Heigl knows how to serve up a heavy dose of back-to-school excitement with an added dash of parental embarrassment. On Aug. 27, she shared a video of her singing her daughters a cheer on Instagram, and the kids look less than thrilled! "First day of school for my gorgeous girls!" she captioned the video. "Yeah, I came up with an embarrassing cheer this morning laying in bed and couldn't wait to sing it for them. The good news is . . . I did not do this in front of their classmates!"