Coachella 2014: Beyonce stuns fans with impromptu duet with sister Solange

The 'Drunk in Love' singer was not officially on this year's line-up

Singer Beyonce performs with her sister Solange onstage on Day 2 of the 2014 Coachella Valley Music & Arts Festival (Getty Images)

Beyoncé surprised the crowds at the Coachella Festival after she made an unexpected appearance alongside her younger sister Solange.

The singer, who was not part of the official line-up, joined her sibling on stage yesterday for an impromptu rendition of ‘Losing You’.

The pair had also choreographed a dance routine beforehand for the joint performance.

Solange sang a solo number before Beyoncé took to the stage for the duet on the second day of the festival in Idio, California.

Fans shared their shock on social media: Twitter user Jason Lipshutz said “ALMOST didn't stop by Solange. But it was "Losing You" so we watched. Then Beyoncé came out. Lesson: ALWAYS watch Solange. #coachella”.

Taryn Brooks tweeted: “Beyonce dance cameo with Solange at Coachella just blew my mind. They are amazingggg [sic]”.

The 'Drunk in Love' singer had been spotted earlier on in the crowds with her husband Jay-Z, who is one of the artists in this year's line-up.

Other acts performing on Saturday evening were New Zealand singer Lorde, Pharrell and Kid Cudi.

The annual two-weekend festival started on Friday and will finish on 20 April, this year’s headlining acts include OutKast, Muse and Arcade Fire.

The Coachella Valley Music and Arts festival first started in 1999 and has been growing in popularity and attracting bigger crowds and acts ever since then.

Read more: Festival guide 2014: Coachella, Glastonbury, Reading - everything you need to know