Selena Gomez and Justin Bieber shocked fans last night by releasing a song about their relationship – but deleted it hours later. 

The song literally came out of nowhere on Drake's OVO sound radio show. Titled Strong, the duet is a reference to their famous on-again-off-again relationship.

Although the two are no longer together, the lyrics certainly tell of a complicated past as a couple in the spotlight. 

"What should I do? Should I go? Who do I talk to? Nobody knows," sings Bieber. 

Later Selena sings, "Wishing I was better at this damn thing 'cause it's just been too long and I can't change."

It is still unknown if the release was deliberate as it was only briefly accessible before it disappeared.

The Daily Mail reported that the duo have been planning the collaboration for some time now as they felt it would be therapeutic.

Selena recently released her latest Album, Revival, on which her single Good For You shot to number five on the Billboard Hot 100.

Meanwhile, Justin has been teasing his upcoming album, Purpose, which is set to be released on November 13.