Pop star Lady Gaga on Tuesday announced a line of beauty products exclusively for sale on Amazon in a boost to the online retailer’s cosmetics business. The brand, Haus Laboratories, will launch in September for shoppers in nearly a dozen countries, including the United States, Germany and Japan, Amazon said. The move underscores how the world’s biggest online retailer is increasing competition with traditional cosmetics sellers like Ulta Beauty and Sephora-parent LVMH, which recently launched a beauty brand by singer Rihanna.Lady Gaga said Amazon was the right partner because it embraced her message of self-acceptance. “There are companies that see me and what I stand for and the way that I view the world, and if it’s not perfectly in line with what they do ... they’ll be like, ‘Can you just change half of the equation?’” the singer told publication The Business of Fashion, which reported the news earlier Tuesday. “The answer is no. No deal.”