Carlos Alcaraz will face Alex de Minaur in the Queen's final for the chance to win a first grass title and return to world number one before Wimbledon.
Spanish top seed Alcaraz, 20, swept past American Sebastian Korda 6-3 6-4.
Earlier on Saturday, Australian De Minaur beat Danish second seed Holger Rune 6-3 7-6 (7-2).
A win at the London tournament would lift Alcaraz above Novak Djokovic in the rankings and make him top seed for Wimbledon, which starts on 3 July.
"At the beginning of the week I didn't know that a good result would put me number one but in the press conference yesterday they told me and I thought 'oh my god - it's in my mind, I'm going to go for it'," Alcaraz said after his win over Korda.