The wait is over, Kellan Lutz fans. Behold his just-released Calvin Klein ad, and man is it HOT! As promised, the Twilight hunk is stripped down to his undies to launch the new CK X Underwear range.So, what was the motivation for Lutz to appear in the ads? He explained,"I started out modeling so this is the pinnacle. What more can you do than be on a billboard for something that you grew up thinking was super sexy and classy?