Foy was accompanied by her ‘The Crown’ co-star Matt Smith at the 75th annual awards ceremony on Sunday 7 January.
Eagle-eyed fans were also pleased to see she accessorised her look with a badge on her sleeve that says “Actresses Equal Representation” and “50:50.”
The second Foy made her entrance Twitter Could. Not. Cope.
Perhaps Foy was paying tribute to Jane Fonda - one of the first women to wear a plain black, off-the-rack suit (Yves Saint Laurent) to the Oscars in 1972, according to Vogue.
“I felt it suited the somber times,” Fonda once said of the outfit.
“Besides, I wasn’t into buying fancy dresses when the Vietnam War was still being fought.
“I wore something that made a statement. It was not a time for showy dresses. It was a time for seriousness.”