(born June 14, 1993) is an American actor and singer. As an actor, he is known for his recurring role as Diggie on the Disney Channel sitcom Liv and Maddie, and for his role as Brad Majors in the 2016 Fox musical television film The Rocky Horror Picture Show: Let’s Do the Time Warp Again. McCartan is also known as one half of the pop duo The Girl and the Dreamcatcher. McCartan also played Jason “J.D.” Dean in the Los Angeles (2013) and the original off-Broadway (2014) versions of Heathers: The Musical.
Starting in 2013 McCartan began playing the recurring role of Diggie on the Disney Channel comedy Liv and Maddie. In 2015 he starred in the direct-to-video film R.L. Stine’s Monsterville: Cabinet of Souls. In 2016 McCartan was cast in the lead role of Brad Majors in the 2016 Fox musical television film The Rocky Horror Picture Show: Let’s Do the Time Warp Again.
Beginning September 11, 2018, McCartan made his Broadway debut as Fiyero in the musical Wicked.