Carrie Underwood Goes Prehistoric on 'How I Met Your Mother'

Carrie Underwood makes her sitcom acting debut on CBS' "How I Met Your Mother" -- and ET has a sneak peek as she shows off her acting chops.

The Grammy Award-winning singer will play Tiffany, a pharmaceutical sales rep who becomes a love interest for Ted (Josh Radnor).

When the gang brings it to Ted's attention that he is being strung along by Tiffany, they reflect about relationships where each of them has been in the same situation, and, of course, Barney (Neil Patrick Harris) has his own unique take on the situation.