相葉雅紀 (Masaki Aiba) is a member of the Japanese boy band 嵐(ARASHI). He is a Japanese idol, singer, actor, television show host, radio host, and dancer.

Born December 24, 1982, in Chiba city, Chiba, he joined Johnny & Associates in 1996 at the age of 13 and began his career as a stage actor with the adapted stage play “Stand by Me”, which was performed with future bandmates Kazunari Ninomiya and Jun Matsumoto in 1997.

On September 15, 1999, Aiba debuted as a member of ARASHI and started his career as a singer. He has also been building his career in many varieties shows since then, especially regular appearance and later co-host on 天才！志村どうぶつ園, a Japanese famous animal TV show created by 志村けん (Ken Shimura) which broadcasted over 16 years. He has been dealing with the abused and rescued dogs' problems through this TV program. The program made him recognize the impact he can bring to those in Japan and decided to raise awareness on dog abuse and rescue. Since 2018, he has groomed more than 35 rescued dogs.

His hosting TV show, 相葉マナブ, in which he learns the splendour of Japan, has been broadcasting over 7 years. In 2016 Aiba hosted グッと！スポーツ, a program about sports on NHK which interviews athletes aiming for Tokyo Olympics and Paralympics. He later served as the NHK Tokyo 2020 Olympics and Paralympics broadcasting special navigator with Sho Sakurai, a member of ARASHI.

Aiba also has a radio show called レコメンアラシリミックス, aired for more than 20 years. He has also appeared in more than 35 TV dramas and movies.