"Let's just say that there's a bucket list and there's a bucket list, and one is completely filled and the other one has a way to go," Tom said, as co-star Hugh Grant gave an affirming chuckle.
The movie, written and directed by Tom Tykwer and the Wachowski siblings, sees the main characters in the past, present and future, which meant long hours in the makeup chair.
"I love that part of it," said Halle, who was intrigued by the transformations. "Yes, it would be makeup for sometimes eight, nine hours and then nine hours of working, so the days were long but that was the fun of it."
Tom said he was initially drawn to the project simply because he'd "never seen anything like it."
"It was a petrifying screenplay to read," Tom explained. "It was more than just a challenge. It was going to be a thing where everybody was going to have to be on their absolute tippy toes, not just of their game but also of their psyche and their energy."