AP Photo/Peter Kramer
Judging by Anne's "Yeah, I know we look ridiculous, thankyouverymuch" face, we're guessing this was not her idea. So we're going to put the blame on boy-crazy Kate, who probably coerced Anne into this using Katy Perry as scientific evidence that this would be awesome.
Unless the his 'n' hers ensembles were just one big coincidence. What's your guess?