Singer Katy Perry believes in angels and aliens.

The 29-year-old noticed a white feather float past her during her recent performance and believes it is a sign that angels are protecting her, reports femalefirst.co.uk.

In a series of Twitter posts, she revealed: "My favorite part of the night was when I was singing 'By the Grace of God' & a little white feather (presumably from a costume) floated by..."

"& it reminded me about the angels & how, maybe, they are still looking after me, helping me continue to put one foot in front of the other."

As well as believing in angels, Perry also believes in aliens.

The "Roar" hitmaker, who was raised by strict Christian parents, has become increasingly interested in extra-terrestrials.

"I'm fascinated by that kind of stuff because of how I grew up, where everything was so black and white. Now I'm seeing a lot more colour in the world and asking more questions."

"So, I'm very into things that are above and beyond me and were before me and will be after me... I do hope that when the aliens come, they'll recognise me. I'll be like, 'Please don't kill me, I wrote a song called 'E.T.'," she added.