In an interview with El País in March 2009, Pedro Almodóvar revealed that the idea for the lip reader played by Lola Dueñas came from watching the wedding of the Prince and Princess of Asturias on Spain's Telecinco, where the services of a lip reader were employed by the channel to relay what the couple were saying to each other as they stood at the altar.
Pedro Almodóvar has said that one of the reasons he decided to hire cinematographer Rodrigo Prieto is because he knew the movie was going to be colorful, and Mexicans are not afraid of colors when it comes to be visual.
The sex scene between Penélope Cruz and José Luis Gómez was changed on set. When they were going to shoot, Pedro Almodóvar decided to start the scene with the couple having sex under the sheets, so the audience didn't know for a while if Lena was having sex with Mateo or Ernesto.
The photograph featured in the film of Harry and Lena embracing on Golfo Beach in Lanzarote has its roots in a real life photograph Pedro Almodóvar took of Golfo Beach whilst there in 2000. When he had the photograph developed, the director saw at the bottom of the photo a couple he hadn't noticed on the day embracing. "I felt that the couple hid a secret", he said later. "The whole island was holding a secret. I had to unveil that secret."
This film was a deliberate reunion by Pedro Almodóvar with a lot of actresses who have worked with him over years. Not only Penélope Cruz and Blanca Portillo, but small parts for Ángela Molina, Chus Lampreave, Lola Dueñas, Carmen Machi, Rossy de Palma and Kiti Mánver.
The short film La concejala antropófaga (2009) came about because of this film. Pedro Almodóvar was so happy with Carmen Machi's performance in this movie that he wrote her monologue from the short the night after she shot her scene. The next morning, Almodóvar approached Machi with the script, and they filmed it that day.
Agustín Almodóvar: Pedro Almodóvar's brother, and the film's producer, appears as an employee of Ernesto Martel, in the scene where Lena returns from hospital. Agustín has cameos in 15 of the 17 films which Pedro Almodóvar has directed.
The trivia item below may give away important plot points.
The roundabout where the main characters have a car accident is the same one where local artist César Manrique died years before in a car accident. César Manrique guided director Pedro Almodóvar in his first visit to Lanzarote, the island where the movie was filmed. Almodóvar has said he was not aware of that fact, and that he found out about it from the news.