The 30-year-old, who recently got engaged to Kris Humphries, thinks that working out makes her feel good about herself.
She told British More! magazine: 'I'm at my sexiest right after I leave the gym. I always feel so good, I also like being glammed up though.
'Every girl has their insecurities but I have just become more comfortable with my body as I've grown older.
'Although I do work out hard, there is always room for improvement. If I'm at home I work out every day, but with travelling so much it's hard.'
The Keeping Up With The Kardashians star also believes that confidence is the key to feeling sexy.
She added: 'Confidence is sexy. If someone is really insecure, they can come across as really unsure of themselves.
'And if you have body issues, it can roll over into your work and the rest of your life. I think confidence is just the sexiest thing.'