SJ, or Super Junior, is a popular South Korean boy band formed in 2005 by SM Entertainment. Known for their diverse music styles, including pop, R&B, and electronic, they have gained a massive following both in South Korea and internationally. The group originally debuted with twelve members, but the lineup has changed over the years. The band is recognized for their energetic performances and catchy songs, such as "Sorry, Sorry" and "Mr. Simple." SJ has also ventured into various entertainment fields, including acting and hosting, further solidifying their status in the K-pop industry.