Masato Hayakawa, known professionally as Masato, is a Japanese-American singer, musician, songwriter, producer, and model. He is best known as the lead vocalist and bandleader of the Japanese rock band coldrain, which he co-founded in 2007. Prior to coldrain, he was a member of the band AVER alongside future coldrain drummer Katsuma Minatani.

Born in Nagoya, Japan, to a Japanese father from Niigata and an American mother from Iowa, Hayakawa was raised bilingual. His mother, an English teacher, taught him English from a young age—something he once disliked but now credits as crucial to his international career. He spent many summers in the U.S., where, at age 13, he was inspired by watching music videos from Limp Bizkit and Korn, leading him to pursue music.

Masato began playing guitar in middle school and later attended Nanzan University to study law, aspiring to become a sports agent. However, he left the university after two and a half years to fully commit to his music career. Beyond music, he is also a fashion designer and model, serving as the director of a clothing line and modeling for Over(all) Tokyo.

Masato has maintained a close creative relationship with ONE OK ROCK, collaborating with them both in the studio and on stage. He was featured on the track “Skyfall,” released in 2017 as part of ONE OK ROCK's deluxe international project alongside other vocalists such as Koie from Crossfaith. His distinctive vocal style added depth and aggression to the song, complementing Taka's lead. Masato also joined ONE OK ROCK on stage to perform Skyfall live during their ONE OK ROCK 2018 AMBITIONS JAPAN DOME TOUR at Tokyo Dome on April 4 and April 5, 2018, where the collaborative energy between the bands captivated fans.

In addition to performing, Masato contributed as a co-writer on the track Renegades (2021), a powerful single co-written with Ed Sheeran, Taka, Jin Jin, and David Pramik. Although he does not perform on the track, his songwriting input speaks to the creative trust and shared vision between him and ONE OK ROCK. Through these collaborations, Masato has established himself not only as a dynamic performer but also as a key creative partner in ONE OK ROCK's international projects.