Niall Horan doesn't think he will be able to perform when he is 70.

The 20-year-old One Direction star doesn't anticipate entertaining future generations for years to come like Rolling Stones frontman Sir Mick Jagger - whose career has spanned over 50 years - blaming his ''dodgy knees.''

The star said: ''Jagger does it but I don't think at the moment I'd be able to. I've got dodgy knees.''

The teen heartthrob's bandmate, Harry Styles, is also in awe of Mick and is hoping to have a long standing career like him.

Earlier this year the curly-haired hunk took up ballet in an attempt to emulate the rock star's dancing skill and decided to copy part of Mick's fitness regime following a chat with the music legend's long-standing trainer and physio Torje Eike.

A source previously said: ''Harry wants a career spanning decades like Mick's and to have that he recognises fitness, health and developing his body is the key.

''He spoke to Torje about Jagger's intense routine of kick-boxing, running, weights and, most importantly, ballet.

''That's the Achilles' heel in Harry's training. He can't dance and neither can any of the 1D boys - their choreographer recognised early on they shouldn't dance on stage.''

One Direction - which also includes Zayn Malik, Louis Tomlinson and Liam Payne - are currently on the Australian leg of the tour where they are set to take to the stage at Melbourne's Rod Laver Arena tonight (17.10.13).