The 38-year-old singer shot to global fame when the Spice Girls became a global phenomenon in the mid-90s, and with the boy band - made up of Niall Horan, Zayn Malik, Liam Payne, Harry Styles and Louis Tomlinson - echoing their success, the pop veteran believes they should make the most of their fame because it can be so fleeting.
Speaking to heat magazine, she said: ''They seem to be breaking America, which we were lucky enough to do. My advice would be just enjoy it, because so often with success like that, it's over so quickly.
''Really enjoy every minute of it. Try and take it all in, because it's crazy.
''With pop bands, [fame] is often so short-lived that you have to take every opportunity that you can, and it is hard.''
The 'Jesus Christ Superstar' musical star has also urged the boys to get as much rest as they can between concerts and recording commitments and try not to get caught up in the partying lifestyle.
She added: ''I would say that you have to rest as much as you can. I think it's harder for boys, as well, but there's lots of evidence that they like a bit of a party. There's no time for hangovers, really. It can be difficult, but I have no sympathy. Just enjoy it.''