LONDON, ENGLAND – AUGUST 03: Sienna Miller attends the World Premiere of “The Sandman” at BFI Southbank on August 3, 2022 in London, England. (Photo by David M. Benett/Dave Benett/WireImage)

They say 30 is the new 20, but if Sienna Miller is anything to go by, 40 is. The actress has been having the summer of a lifetime, filled with festivals: for Glastonbury’s return, she donned her festival best, alongside fellow stylish Glasto regular Alexa Chung, making headlines yet again for her perfect boho style.

Miller then swapped to white, wearing her courtside best to join her (very hot) Burberry model boyfriend Oli Green in the stands at Wimbledon, before taking off to Saint Tropez at the end of July for an ultra chic vacation. 

GLASTONBURY, ENGLAND – JUNE 24: Sienna Miller and Oli Green attend day three of Glastonbury Festival at Worthy Farm, Pilton on June 24, 2022 in Glastonbury, England. (Photo by Samir Hussein/WireImage)

Now, adding the final piece to the puzzle: a red carpet event. On Wednesday night in London, Miller attended the premiere of Netflix’s new film, The Sandman, wearing an elegant but still relaxed and low-key look made up of a dress by British brand Self-Portrait.

For the occasion, which was held at the BFI in London, Miller donned a fitted ribbed-knit dress by the brand in baby blue, with flared sleeves and a keyhole cut-out at the sternum. Stopping just above the ankle, Miller complimented the pastel colour with white strappy sandals from The Row and carried Prada’s cult Cleo bag also in white.

LONDON, ENGLAND – AUGUST 03: Sienna Miller attends the World Premiere of “The Sandman” at BFI Southbank on August 3, 2022 in London, England. (Photo by David M. Benett/Dave Benett/WireImage)

Pulling her signature blonde hair back off her face into a messy bun and adding a swipe of pink to her lips, Miller showcased exactly how to dress to steal the show while looking like you just rolled out of bed and threw a look on. 

Interestingly, Miller’s link to the film is that of her ex-boyfriend and father of her daughter, Marlowe, Tom Sturridge. Sturridge, who now happens to be dating the aforementioned Chung, is the lead character in the supernatural series. Though Chung herself wasn’t photographed at the event, she did attend Wimbledon alongside Sturridge, Miller and Green last month. 

LONDON, ENGLAND – JULY 03: Tom Sturridge, Alexa Chung, Oli Green and Sienna Miller attend the All England Lawn Tennis and Croquet Club on July 03, 2022 in London, England. (Photo by Karwai Tang/WireImage)

Oh, and to top it all off, Miller’s career is going well, too: she was just cast alongside Scarlett Johansson to star as sisters in Kristin Scott Thomas’s directorial debut, My Mother’s Wedding. We love to see it.