"I Know What You Did Last Summer" is a song by Canadian singer Shawn Mendes and Cuban-American singer Camila Cabello. The song serves as Cabello's debut single as a solo artist and was released as the lead single from the reissue of Mendes' debut studio album, "Handwritten Revisited" (2015), via Island Records on November 18, 2015. It reached the top 20 on the US "Billboard" Hot 100 and on the Canadian Hot 100. Mendes and Cabello promoted the song with several televised performances, including on "The Tonight Show Starring Jimmy Fallon" and at the 2016 People's Choice Awards. Mendes and Cabello later collaborated on "Señorita" in June 2019.