"Deja Vu" (stylized in all lowercase) is a song by American singer-songwriter Olivia Rodrigo. It was released on April 1, 2021, through Geffen and Interscope Records, as the second single from her debut studio album, Sour (2021). Rodrigo wrote the song with its producer Dan Nigro, with Taylor Swift, Jack Antonoff, and St. Vincent receiving writing credits for its interpolation of Swift's 2019 song "Cruel Summer". An incorporation of various pop and rock sub-genres, "Deja Vu" explores themes of nostalgia, heartbreak, and the complexity of moving on from a past relationship. Olivia Rodrigo reflects on the memories associated with her previous relationship and the struggle to let go, even as she acknowledges that the new couple is creating their own memories.