Taylor Swift's "muscle memory" saves her when she forgets song lyrics on stage.

The 25-year-old pop star is currently busy touring the world with her 1989 album but is also entertaining fans with some of her older tracks.

Even though she's been singing some of these for years, Taylor still occasionally finds herself in a position where she forgets the words. Luckily her instinct jumps in to rescue her.

"This is weird, but usually muscle memory picks it up," she explained to BBC Radio 1.

"Sometimes I'm like, 'I literally have no idea what the line after "I knew you were trouble when you walked in" is,' but then I just sing it and I had no idea what it was, but I just sang it."

Blanking out on stage isn't the only potential touring hazard, with Taylor admitting that being sick while on stage is one of her biggest fears. While she doesn't find her job hard, there are certain other things she has to bear in mind.

"You have to get used to not eating a lot after show or you'll get tour fat; it's a thing!" she laughed.

"It's not that hard, I'm telling you right now, there are just some things you have to adapt to. You have to adapt [to]: 'What if it rains?' You have to keep going, even if you're feeling really sick, you have to accept the fact that at a certain point you'll sweat so profusely, you don't look pretty and your hair is stuck to your face - and that has to be OK with you."