Image via Getty.

Sienna Miller had everyone calling their hairdresser late last year when her gorgeous tousled lob stole the spotlight at every major red carpet event.

Now, she’s made another big switch. And her latest look? It’s just as chic and effortlessly cool.

The 33-year-old actress has farewelled her signature blonde, and welcomed in a rich, red shade just in time for autumn (she lives in the UK, remember).

Considering how popular her blonde lob was, we're predicting women the world over will start replicating this new look with equal enthusiasm. After all, Sienna Miller is nothing if not a trend setter — she was single-handedly responsible for many of those ubiquitous boho trends of the mid-noughties.

Miller introduced us to her new look at the London launch party for her sister's Debenhams fashion line, Nine by Savannah Miller.

Miller has coloured her blonde hair for her role in The Lost City of Z, which she's been busy shooting in Northern Ireland.

If you need any more temptation to book in for a chop or new colour, check out a few of our other favourite celebrity hair changes of late:

The best celebrity hair transformations

Dakota Johnson.

attends a photocall for 'A Bigger Splash' during the 72nd Venice Film Festival at on September 6, 2015 in Venice, Italy.

katie holmes yoga hair

Katie Holmes' new hair on Instagram.

jess alba shoter hair aug 15

Jessica Alba's shorter, lighter 'do. (Source: Instagram.)

Britney Spears

Lily Allen

Katherine Heigl

GiGi Hadid.

Gigi Hadid wearing a classic, matte brown lip. (Source: Instagram.)

Selena Gomez.

Katy Perry.

cara pink hair 2

Image via Instagram.

phoebe tonkin new hair

Image via Instagram (@phoebejtonkin)

rebecca gibney new hair

giuliana-rancic-short-rose-hair

Jessie J

It's soooo loooooong.

Jenna Dewan-Tatum

Britney Spears

Check out those purple ends

natalie imbruglia hair

Emilia Clarke

Abbey Lee Kershaw

Alanis Morissette

Anna Kendrick

Zoe Kravitz

Laverne Cox

Kate Mara

Kaley Cuoco

Kaley Cuoco

Madonna