Jedward joined Britney Spears on stage last night (October 28) during a London date of her 'Femme Fatale' world tour. 

The X Factor duo were also invited to meet the pop legend backstage. 

"We are gonna get to meet Britney spears (sic)," they wrote on Twitter. "it gonna be the Biggest Moment of our Life! And the biggest Moment for Jedward Fans.

"We are gonna get to Perform with Britney Spears Tonight! It's gonna be a JEPIC moment and we are gonna relive it and remember it for life!"

The Irish stars sent a good luck message to Spears saying: "you are totally awesome you are gonna Rock Tonight!" and encouraged fans to tweet their excitement for the upcoming "performance of the year". 

"Everyone needs to know this is a very very exciting moment!," they added. "Every interview we have ever done has always had us talking about."

Jedward returned to Twitter ater their on stage appearance and prepared for a more intimate meeting with the superstar. 

"we are backstage! This the most coolest thing eveeeeeeer!" they wrote. "It's craZy we are gonna be breathing the same air! It's Britney Air! #JEDWARDLoveBRITNEY #JEDWARDmeetingBRITNEY"

Jedward are set to represent Ireland in next year's Eurovision Song Contest.

Watch a video of them performing with Britney Spears on stage, below: