"I'll forever regret this look," Turner admitted. "One of my worst looks."
But mistakes happen, as it was a very last-minute decision to wear the ensemble.
The British star packed two "classy" dresses for the big day but didn't try them on until last minute - only to find that they didn't fit.
"I had a fashion emergency," she recalled. "It was either the thigh-high boots or these nice heels but I felt like if I just wore the heels all of my leg is showing, if I cover up a little bit then... urgh, it was a disaster. Worst fashion choice."
Thankfully, she has worn a number of headline-worthy outfits to make up for the sartorial mishap.
One of her favourites so far is the Alexandre Vauthier gown she donned for husband Joe Jonas' 30th James Bond-themed birthday bash.
Clearly a celebrity crowd-pleaser, Taylor Swift also wore the look to the Vanity Fair Oscars after-party back in 2016.
Speaking about matching with the American songstress, she added: "I wanted to be a Bond girl for the night... I know that Taylor Swift wore this before to an event and she looked much better in it than I did."
Turner looked pretty great, if you ask us.
This article originally appeared on InStyle Australia.