Katie HolmesIf you are the type to buy into viral marketing plays, perhaps you might care to hazard a guess as to the identity of the actress in this short clip.

Elle magazine creative director and sometime reality TV star Joe Zee promises to reveal all on March 22, including exactly what the "What's in the Bag?" campaign is meant to be advertising.

Beyond knowing that the product is in the fashion and/or beauty sector, StyleList was strongly encouraged by an insider to believe that the mystery brunette is Katie Holmes.

We were told the person is "a famous actress who the tabloids are always saying is about to leave her partner, playing Joan Hudson, a famous actress who is leaving her partner." Watch the ad after the jump.