The lyrics of Stay Calm, Stay Peachy Shop and Stay Awake all remain calm and composed, according to the BBC.
The songs are the second best-selling singles of all time.
The two songs have sold almost 10 million copies, according a study from Nielsen Music.
Stay Calm has sold more than 11 million copies worldwide.
The duo released a remix of the songs in 2016, and in 2017, they released a full-length album, Stay Awaken, to mark the release of their seventh album, Be Still.