Union J are "buzzing" for their performance at Capital FM's Summertime Ball 2013 tomorrow (9th June).

The former 'X Factor' finalists took to Twitter today to share their excitement ahead of the big annual music event after finishing their rehearsals and sound check.

JJ Hamblett tweeted: "Great rehearsals today!! Buzzing to perform in front of 80,000 at Wembley Stadium tomos!!! Bring it on whoop JJX (sic)."

Hamblett, Josh Cuthbert, George Shelley and Jaymi Hensley will make their debut at the event tomorrow, alongside a star-studded bill including The Wanted, The Saturdays, Jessie J, Olly Murs, Taylor Swift, will.i.am, with international superstar Justin Timberlake hosting the event.

Rizzle Kicks explained that they can't wait to take to their stage after performing alongside Jessie J last year.

Jordan Stephens gushed: "I'm over the moon!" while bandmate Harley Alexander-Sule explained: "I can't wait. We jumped on stage with Jessie last year, but it's great to do it this year, on our own! It's going to be pretty awesome."

Ellie Goulding - who recently played at the Chime For Change concert last weekend at Twickenham Stadium in London - is looking forward to seeing her pop counterparts take to the stage tomorrow.

She said: "To be honest, my life is as usual – completely mental so it's just another day in the life because I was playing a stadium the other day and now I'm playing another one. But this one's going to be wicked because I can watch some amazing people perform."

She continued: "So it's going to be very different but, yeah I'm getting a bit excited now. It is a stadium after all so it's quite a big deal."