One half of the identical brother duo known as Marcus & Martinus who performs alongside his brother Marcus. They won the 11th season of Melodi Grand Prix Junior. They have released albums called Hei, Together and Moments.
He and Marcus were just 10 years old when they won the Melodi Grand Prix Junior competition.
He and Marcus have released two books about their life. The music video for their song "Elektrisk" became one of the most viewed Norwegian YouTube videos of all-time.
He and Marcus were born in Elverum, Norway. They also have a sister named Emma.
He and Marcus won Melodi Grand Prix Junior two years prior to Mathea-Mari Glittenberg.