Kelly Rutherford was taken aback over news of Kate Middleton’s pregnancy. The “Gossip Girl” star was overheard joking in mock disbelief, “Does that mean they’re having sex?” about the royal fertilization. “This is crazy,” she added at Ermenegildo Zegna’s launch of its Essenza fragrances this week on Fifth Avenue. “I thought they had to sleep in separate rooms and everything.” Also in attendance at the launch were “Today” host Matt Lauer, Solange Knowles, movie director Ed Burns, “Twilight” saga star Peter Facinelli, “Good Morning America” anchor Josh Elliott, ABC’s Dan Abrams, Scarpetta chef Scott Conant, Gildo Zegna and Estée Lauder executive Fabrizio Freda.