Margot Robbie has your back when it comes to THIS classic makeup fail

It took us most of our teenage years to master how to blend our foundation into our jawline, but once we had that down, we thought we were sorted.

We weren't, of course, because while we were busy dealing with our jawline, we were completely neglecting another line – our hairline, obvs.

If you've ever arrived to work or college and realised your base is giving your hair a grey tinge akin to your granny's 70th birthday snap, then you're not alone.

And if you're one of those girls who used your fringe to avoid properly blending your make-up, then meet your sisters.

But it looks like we need no longer fear the washed-out septuagenerian look if Margot Robbie's recent tips are anything to go by.

Speaking to ELLE, the Aussie star revealed her top trick for avoiding the look we've spent too much of our life rocking.

"My friend taught me this trick that I use it every day. When I put on foundation, I use an eyebrow brush or toothbrush to brush it into my hairline so that it all blends," she explains.

"Especially because I have blond hair but tanned skin, if I don't blend it, it looks gross – you can see the foundation in my hair."

Unlike the rest of us however, Margot's boyfriend struggles to understand much of her beauty routine.

"I do that every single day, and every time my boyfriend [Tom Ackerley] is like, what are you doing? And I'm like, I'm brushing my makeup into my hairline! And he's like, girls are crazy."

Crazy… but perfectly blended thanks to your girlfriend, Tom.