Marketa Vondrousova became the first unseeded player to reach a Wimbledon women's singles final after ending Elina Svitolina's inspired run.
Vondrousova, 24, had never gone past the second round at the All England Club until this year.
But she is now one win from glory after beating Ukraine's Svitolina - also unseeded after giving birth nine months ago - in a 6-3 6-3 win.
Vondrousova will play Aryna Sabalenka or Ons Jabeur in Saturday's final.
Belarusian second seed Sabalenka meets Tunisian sixth seed Jabeur in Thursday's second semi-final, which follows on from the first match on Centre Court.
Whoever advances, it is guaranteed there will be a first-time champion at the All England Club.
"I can't really believe it," said Vondrousova, who had never played on Centre Court before.
"I'm just so happy. Elina is such a fighter and also a great person. It was such a tough match."
Vondrousova ends Svitolina's stunning run
Recent history has provided a number of shock Grand Slam finalists in the women's singles, but Vondrousova's progress is probably as big a surprise as there has been at Wimbledon in the past decade.
Vondrousova, ranked 42nd in the world, admitted before the semi-final she "never thought" she could do well on grass.
Clay courts have long been considered the Czech's best surface and she has reached a major final before, losing to Australia's Ashleigh Barty in the French Open final in 2019.
But she has grown in belief during the grass-court major, cleaning out four seeded opponents before facing former world number three Svitolina.
That confidence was illustrated as she started strongly. Vondrousova targeted Svitolina's backhand and reaped the rewards with two breaks of serve in a run of three games against serve to lead 4-3.
Vondrousova's loopier forehand caused problems for Svitolina, who hits a flatter ball, and greater consistency from the baseline enabled her to break again in the ninth game to seal the set.
The run of Svitolina has been one of the storylines of the fortnight.
Not only is she coming back from giving birth to daughter Skai in October, the Ukrainian is also dealing with the emotional aspect of the war back home, which she says she has used as added motivation to win matches.
As usual, Svitolina showed her determination and will to win even when she fell 4-0 down in the second set and the match looked to be quickly running away from her.
But she clawed back one break - and then the other - providing herself with hope of a remarkable comeback.
However, Vondrousova managed to recover from her edginess to break again and held her nerve in a tense service game to secure victory.