YouTube and musical.ly star alongside his identical twin brother Harvey Mills. Known on musical.ly as MaxAndHarveyOfficial, they have earned over 5 million fans. They have released singles such as "One More Day In Love" and "Stuck on the Ceiling."
He and Harvey have acted in commercials, television shows, and in West End Theater productions such as the Sound of Music UK Tour.
He and Harvey began harmonizing together at the age of five. He started playing the guitar when he was eight years old.