Osamu Adachi (足立 理, Adachi Osamu?, born December 22, 1987) is a Japanese actor and a member of the acting group D-BOYS. He is best known for his role as Eiji Kikumaru in The Prince of Tennis musical series, Tenimyu, and in the live film adaptation.

In October 2004, Adachi joined the Watanabe Entertainment group named the D-BOYS. He took part in TV shows and has appeared in GLAY's "White Road" (2005) music video. He was also apart of the Watanabe net drama "Hice Cool" (2005) and "DD-BOYS", appearing alongside fellow D-Boys members. But, by the end of January 2007, it was announced to fan club members that while Adachi was still being represented by Watanabe Pro, both he and Yuma Minakawa had officially withdrawn from the group. In April 2008, however, it was announced that Adachi would be re-joining the D-BOYS and participating in the second D-Stage. The reason given for his former withdrawal was that he had been studying acting at a university, and also that he had been feeling self-conscious about his abilities.

In 2004, Adachi won the role of Eiji Kikumaru, the acrobatic player of Seigaku Middle School's tennis club, in the Prince of Tennis musicals, Tenimyu. From 2005 to 2006, he became the third actor to play Kikumaru as a member of the second generation Seigaku cast. He made his debut as Kikumaru on January 8, 2005 in the Side Yamabuki performance in Osaka. That same year, his role as Kikumaru was carried into the live adaptation film of the manga. During his run in the musicals, he was able to work with fellow D-BOYS members Yuya Endo, Kotaro Yanagi, Masaki Kaji, Hiroki Suzuki, Hirofumi Araki, Masato Wada, and former member Yuu Shirota.

On March 29, 2006, in the Dream Live 3rd live concert, Adachi, along with the majority of the Seigaku cast, graduated from their roles. Since his graduation, the role of Kikumaru has been played by D-BOY member Koji Seto, and currently by actors Kyousuke Hamao and Shouta Takazaki.

Adachi was able to carry on his role from the musicals to the live-adaptation film of the manga series of The Prince of Tennis. He, along with most of the principle cast members for the Seigaku Regulars, were able to reprise their roles in the movie. The only major casting change was the casting of Kanata Hongo as Ryoma Echizen, the main protagonist.

Source: Wikipedia