Katie Holmes' worst nightmare has come true: Her mad crush will soon be spending a lot of time with the planet's most gorgeous creature, Keri Russell. That's right: After months of will-he or won't-he speculation, J.J. Abrams has cast his onetime Felicity muse in Mission: Impossible 3. According to Variety, Russell will portray an agent trainee mentored by Tom Cruise's Ethan Hunt character. The role was originally pegged for Scarlett Johansson, but she dropped out when the pic was delayed. Now, let's have a moment of silence for the Tomkat.