Hard at work on the set of “Burlesque” Christina Aguilera and Cam Gigandet were spotted shooting scenes on Sunday (January 10). Covered in a pink scarf and shades, the “Genie In a Bottle” singer hopped on the back of a motorcycle driven by the “Twilight” hunk, knocking out scene after scene on the Los Angeles, CA set. According to imdb’s website, “Burlesque” is due to hit theatres on Novembe…