Rap star 50 Cent will join Glacéau endorsers Dwight Howard (Orlando Magic), David Ortiz (Boston Red Sox) and American Idol winners Kelly Clarkson and Carrie Underwood in a new Vitaminwater ad, produced for movie theaters. According to the USA Today, 50 Cent and the others will appear in the humorous commercial as cosmonauts being trained by an Russian supervisor. The advertisement will run on 33,000 screens in 5,000 theaters nationwide.