In 2018, Harris joined 26 other celebrities at Metropolis Studios, to perform an original Christmas song called "Rock With Rudolph". The song was released in aid of Great Ormond Street Hospital and was released digitally on independent record label Saga Entertainment on 30 November 2018. The music video debuted exclusively with "The Sun" on 29 November 2018 and had its first TV showing on "Good Morning Britain" on 30 November 2018. The song peaked at number two on the iTunes pop chart.