The X Factor star will release 'You Bring Me Joy' on September 2 through Sony Music and Xenomania.
The video shows Lily on a road trip with friends, during which she has a water fight at a service station and enjoys an evening at the beach.
Lily recently insisted that pop stars don't need to write their own material, saying: "I think a song all depends on if the artist is right for the song and if they connect vocally with it.
"With a lot of my tracks we (Lily and Xenomania) picked them for the album because I connected with them. If I played you a track that I felt I didn't connect with you'd hear a massive difference."
The singer, whose debut album is expected to be released in November, also revealed that she would like to record collaborations with Katy Perry and Coldplay.