Miley Cyrus has her ''own concept of time''.

The 20-year-old singer - who is currently in London promoting her new single 'We Can't Stop' - finds time-keeping difficult and blames her hectic schedule for always being late.

She told the UK's BBC radio 1: ''I'm always late. I have my own concept of time. They told me, 'You have to go on air in 15 minutes' and I was like, 'I'm rushing, I'm rushing!' I was putting different sunglasses in my bag, deciding if I like my nails today, what ring I should wear.

''I'm not too bad. I think some people would say different. But I just have so much going on, you can blame that.''

The star joked she bases herself on the model Grace Jones, who is well known for keeping to her own time schedule and always doing things on her own terms.

She added: ''[Grace Jones] is my role model. [TV host] David Letterman told her she was seven hours late and she just says, 'Yes I am'. That was my favourite thing ever, I loved that.''

Miley also says feels she operates on a completely different time zone in the studio, and prefers to work at night.

She said: ''When you're in the studio there is a different concept of time. I don't ever start working till about midnight.''