In July 2013, Thompson released a cover of Naughty Boy's single "La La La". In August she released 3 different covers: a cover of Taylor Swift's "Everything Has Changed" (as a duet with Gerald Ko), a cover of Passenger's "Let Her Go" and a cover of David Guetta's "Titanium". In September the same year, she released her debut album Bundle of Tantrums which included the singles "La La La", "Let Her Go" and "Titanium". In September 2013, Thompson released a cover of Chaka Khan's "Ain't Nobody". The song featured in an advert for supermarket chain Sainsbury's for their by Sainsbury's range. The song has peaked at number thirty two on the UK Singles Chart. In October 2013 she released the extended play Under the Willow Tree. One of the songs, named "Run", enjoyed mediocre success in Europe and the United States, and it remains a popular song among fans. In early July, Thompson supported Aussie pop phenomenon Cody Simpson on his Acoustic Tour. She finished the Tour in Birmingham, posting a photo of the fans on Twitter and thanking them for their support.