Simon Cowell has made a dig at former 'Britain's Got Talent' contestants.

Simon Cowell

Simon Cowell

The series boss has taken a swipe at some ex-'BGT' acts who turned down the chance to compete in forthcoming spin-off 'Britain's Got Talent: The Champions', despite them finding fame on the talent show.

According to The Sun newspaper's Bizarre TV column, the 59-year-old music mogul said: "We've had acts we've asked to come back and they've said, 'We don't want to compete but can we do a guest appearance and plug our tour'. And it's like, 'No!' "

On the other hand, Simon was seen praising rollerblading siblings Billy and Emily England, who appeared on the programme in 2015 before getting their own Vegas show.

The duo accepted the offer to take part in The Champions' final heat at Wembley Arena.

Simon told them: "You've come all that way to thank the audience for giving you that chance and you put your lives on the line every time you compete.

"So I can't thank you enough."

Simon was recently in floods of tears when he was reunited with BGT's Julia Carlile two years after paying for her life-changing £175,000 spinal surgery.

Julia shot straight to the 'BGT' semi-finals with dance group MerseyGirls, and told judges Simon, David Walliams, Amanda Holden and Alesha Dixon she was hoping to use the £250,000 prize money to pay for an operation to correct her spine.

After the group lost out, Simon made sure he flew Julia out to the USA so she could get the procedure she needed.