Jennifer Aniston says sleep his her best beauty tip.

The 43-year-old actress is known for her youthful looks and she credits that with getting lots of rest and drinking plenty of water.

She said: ''My best tip is sleep. Honestly. Hydration drink a lot of water - and get your sleep.''

As well as getting sleep, Jennifer takes care over her appearance and was recently announced as the face and co-owner of Living Proof hair products and she says it's a company she feels very comfortable with

She told People: ''I've been known for hair for so long and ... it just never felt right. It has to ring true to me, and feel good. That's the thing that's exciting to me [with ownership], to be able to have creative participation and get behind the product in a way that is actually knowing what's happening as opposed to selling what's happening.''

And the products are so good, even fiance Justin Theroux is using them.

She joked: ''He kind of has no choice. It's what's in the shower right now. You know he's a guy, he just goes for what's in the shower. But yes, he's used it.''