"Rockabye" is a song by British electronic group Clean Bandit, featuring English singer Anne-Marie as main vocalist together with Jamaican dancehall singer Sean Paul. It was released on 21 October 2016 and was their first single since Neil Amin-Smith's departure from the group. The song is about hardships of single mothers and alludes to the nursery rhyme, Rock-a-bye Baby.
The song became the UK Christmas number one for 2016 on 23 December 2016. It is the first song in chart history to become Christmas number one after already being at the top of the charts for six weeks. In total, the song spent 9 weeks at the top of the UK Singles Chart while also topping the charts in over 20 other countries.
On 28 October 2016, "Rockabye" entered the UK Singles Chart at number 7. The following week, it climbed to 3, before high performance in streaming got it to number one on its third week. It also became Clean Bandit's first number one single in Australia, and additionally reached number one in Austria, Finland, Germany, the Republic of Ireland, New Zealand and Switzerland. On 23 December 2016, having already spent six weeks on top of the charts, "Rockabye" became the Christmas number one for 2016, making it the first song to do so that was not an X Factor winner's song, charity single, or stunt song since "Mad World" in 2003. However, it sold just 57,631 copies, becoming the lowest-selling Christmas number one of all time due to being helped by streaming (while actually being number two on the sales-only chart).
In the United States, "Rockabye" debuted at number 100 on the Billboard Hot 100 during the week of 24 December 2016. It has since reached the Top 10, reaching a current peak of number nine.