Sebastian Rejman (born 13 January 1978) is a Finnish musician, actor and presenter, known as the singer-guitarist of the rock band The Giant Leap. He has composed and written the band's songs together with Petri Somer.

After The Giant Leap went on a temporary hiatus, Sebastian formed a new band called Sebastian & The 4th Line Band.

Rejman is from a bilingual working-class family in eastern Helsinki and lives in Kallio, Helsinki. He started playing guitar and singing at the age of 14. His musical role models are Elvis Presley and Bruce Springsteen.

Since 2012, Rejman has also worked as a TV presenter as he co-hosted “Talent Suomi” with Lorenz Backman. Since then, he has hosted “Splash” and worked as a backstage reporter for “The Voice of Finland”. In 2017, he starred in the film “Kuudes kerta”.

Since 2018, he has acted in the hospital series “Syke” as trauma surgeon Jesse.

Rejman represented Finland in the 2019 Eurovision Song Contest in Tel Aviv, Israel, together with Darude.

Rejman is engaged to actress Iina Kuustonen and they have two children, a son born in September 2016 and a daughter born in January 2019.