Anastacia was reportedly given a strict set of rules to follow before performing in front of Pope Francis this week.

The 50-year-old singer performed for the head of the Catholic church in a special concert at The Vatican on Saturday (15.12.18) and was reportedly given a list of things she could and couldn't do during the show - including a ban on swearing and provocative dancing, and a rule that she must wear a ''smart and length-appropriate'' dress.

A source told The Sun on Sunday newspaper: ''Anastacia is more used to calling the shots and issuing demands ahead of a performance.

''But a few weeks ago she received an official document which clearly spelt out, in no uncertain terms, the conditions she must adhere to if she wants to perform in front of the Pope.

''Everyone knows Anastacia loves to move a lot on stage and that her stage outfits are pretty risque, as she's partial to showing off her incredible abs.

''The Pope's officials needed to make it clear that there could be none of that.

''Not only would it be highly inappropriate for religious reasons but Pope Francis is about to turn 82. He would probably have the shock of his life if Anastacia started shaking her hips in front of him.''

Meanwhile, the 'I'm Outta Love' hitmaker recently revealed she feels ''sexier'' now that she's in her 50s than she ever did during her 20s and 30s.

Speaking last year, the blonde beauty said: ''I turn 50 next year and I can't wait. I feel wiser, I feel stronger, I feel sexier and more comfortable in my own skin than I ever did in my 20s and 30s when I thought I was Miss Piggy because I wasn't tall with blue eyes and long legs. I was 30 when I was first discovered and was told by record companies and producers that I had to say I was 23.

''I hated lying and after six years I came clean. Hiding my age for that time has made me very proud of my real age. When I was younger I had all sorts of insecurities. I thought I was unattractive. The older I get the more I see myself in a positive way - roll on 50.''