Hollywood can be a tough place to make friends you trust. It's hard finding people you know will have your back when fame and money are part of the equation. This Sunday, Aug. 2, is National Sisters Day, and it got us thinking that sisters who remain close have a huge advantage in the world of entertainment. When you’ve got a built-in BFF who has known you your entire life, it becomes that much easier to get ahead. Check out how these celebrity sisters encourage, collaborate with and confide in one another. And for more on the goodness of sisterhood, check out It Takes A Sister.