Today is Change Your Hair Day in celebrity land. Here's proof.

Image: Getty.

Recently, you’d be forgiven for thinking that conventional hair colours like red, brunette and blonde were a thing of the past. Madonna‘s gone pink, Hilary Duff went from turquoise to grey, Lily Allen seems to have sampled every colour under the sun, and now women everywhere are sporting split-dyed pastel-coloured hair.

But it seems like the rainbow days may be coming to an end.

Because today several celebrities including Emily Blunt and Hilary Duff have stepped out with new hair colours and they’re suprisingly, well, traditional.

Emily Blunt

The sunny shores of Cannes obviously proved to be an inspiration for Emily Blunt, who debuted her new sun-kissed hair on the Cannes red carpet overnight.

While probably best known for her fiery red locks in The Devil Wears Prada, this is not the first time the 32 year-old actress has gone lighter, also sporting blonder hair last year.

Hilary Duff

Hilary Duff is another celebrity who's decided to ditch rainbow hair in favour of the blonde she's known for.

While we loved seeing Duff experiment with her hair, we're not overly surprised by the change (perhaps she ran out of colours to try...). (Post continues after gallery.)

Kate Waterhouse

We're all too familiar with the desire to change our look after a significant event and fashion blogger and columnist Kate Waterhouse is no different.

Waterhouse has revealed that the only thing stopping her from cutting all her hair off after giving birth to her daughter Sophia was her hairstylist, Renya Xydis at Valonz.

Related: Sorry, but your hairdresser totally knows you’re lying about these 8 things.

"She said to me, 'No you can't cut it all off, everyone cuts it off after a baby. If you want a change, go buy a new dress,'" Waterhouse wrote on her blog.

In the end, she ended up going a little bit lighter, thanks to the "fantastic" colourist Amber Pompeii at Valonz.

"I started off with blonder foils but I found it was just a bit too blonde," Waterhouse says.

"Now it's gone to a bit of balayage but it's a bit higher up, so rather than a two tone colour, it goes from my natural colour to the blonde which makes it look a bit more natural." (Post continues after gallery.)

Ironically, her hair has actually ended up longer!

"The last few years I've had my hair quite a bit shorter, and after having Sophia (I think a lot of mums will agree with me here!) I found it really hard to find the time to get my haircut," she says.

"So I was a bit bad in keeping my appointments, so it just naturally got longer. I was after a change, so I actually got what I was after!"

RELATED: The Chop: “A hairdresser fried my hair, so I had to cut it all off”

Amy Poehler

One celebrity going against the trend (which is exactly why we've always loved her!) is Amy Poehler.

The blonde to Tina Fey's brunette mixed things up a few weeks ago when she traded her signature light hair for a punchy auburn colour at The David Lynch Foundation's DLF Live Celebration in Los Angeles.

We couldn't even find previous pictures where she wasn't blonde, so it was a big change for the 43 year-old. Now though? She's taken it a teensy step further, showing off fiery-red hair at Cannes.

It's shiny. It's brilliantly vibrant. Bravo, Amy.

Our verdict? A hair colour worthy of it's own film festival award. (Post continues after gallery.)

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Do you think blondes have more fun?