Princess Leia

In Return of the Jedi (1983), Leia infiltrates Jabba the Hutt's palace on Tatooine disguised as the Ubese bounty hunter Boushh, and brings a captive Chewbacca with her as part of the ruse. She frees Han from the carbonite, but they are recaptured by Jabba. Leia is now chained to Jabba as his slave, outfitted in a metal bikini. After Luke arrives and kills Jabba's Rancor, Jabba sentences Luke, Han and Chewbacca to be fed to the Sarlacc. Lando (disguised as a guard) helps them overpower their captors, and Leia seizes the moment to strangle Jabba with her chain. Luke and Leia swing to safety, blowing up Jabba's barge behind them. Later, the heroes go to the forest moon of Endor to prepare for a battle with the Empire. There, Luke reveals to Leia that she is his twin sister and that Vader is their father. Leia joins Han in leading the Rebels in battle with Imperial troops as the Rebel Fleet attacks the second Death Star. Leia is slightly injured, but the Rebels, with help from the Ewoks, ultimately defeat the forces of the Empire, with the Death Star destroyed once more.

Question: do luke and leia find out they are twins
Answer: yes