Fiennes said Anderson's screenplay was unlike anything he'd ever read. "I responded to Wes, to his spirit and to how he'd written the film. There are certain rhythms and details and we see how constructed and designed they are. As an acting experience it was fantastic. Wes encourages his actors over many, many takes and you feel exhausted but happy because you've been given this great ride. For a filmmaker to be able to make the film they want to make is very rare."
Anderson wrote the part with Fiennes in mind. "This character is quite grand and theatrical and recites poetry and has paragraphs of text," Anderson says. "The crucial thing is that he be a real person - even if he's talking very quickly and is in a situation that doesn't feel like real life. That's what all these actors do: bring these real people to a fantasy context."
As a director himself, Fiennes marvelled at Anderson's meticulous preparation. "I think every single scene has a storyboard reference and on top of that the storyboards are animated and Wes has recorded the voices. I didn't get too obsessed with this because I didn't want to be carrying this animated image inside my head when I was acting, but it was certainly useful. You could understand the shape of a scene and feel where the tone of the film was intended to go."
With his John Cleese-like manic energy, Gustave H is certainly a long way from any other character Fiennes has played and he likes it that way. "In the past I've been asked to consider characters with some sort of psychological disturbance, intellectual misfits or psychopaths, which is I think often because of Schindler's List and maybe because of In Bruges and Voldemort.
"So now I won't be doing any bad guys. But I don't think an actor should too much reflect on how the world sees them. You've just got to follow your own inner instinct."
His gut feeling was what brought him to direct The Invisible Woman, based on Claire Tomalin's book The Invisible Woman: The Story of Nelly Ternan and Charles Dickens.
He admits was no great Dickens fan, despite having played Magwitch in the 2012 feature revival of Great Expectations.
But the movie's screenplay intrigued him because it wasn't a predictable biopic of the writer.
"I think biopics are very, very difficult and this was a great way of looking at Dickens through the central figure of Nelly Ternan and that was what appealed to me."
According to Tomalin's book, Ternan. who was almost 30 years the writer's junior, greatly influenced the writer though has been overlooked in history.
Fiennes: "I have this weird theory that he had an idea of an idealised woman, which he writes in his books. Then he meets Nelly Ternan and he thinks that's her, this is the woman I have been writing about and falls for her."
Still, Fiennes also feels for Dickens' long-suffering wife, Catherine, even if she's depicted as a frump in comparison to the gorgeous Nelly, played by a radiant Felicity Jones.
"Catherine Dickens seems to have been besieged by pregnancy all her life. She was barely a year without being pregnant from the day they were married or certainly every two years she seemed to be pregnant. She suffered from post-natal depression, I think she was a good woman but Dickens almost didn't need a strong woman. He was fiercely active and a workaholic. And he walked, he was an obsessive walker. Not only was he writing these long novels to deadlines, but he was editing a weekly magazine. He took on so much. He was sort of almost mad with this furious energy."
Dickens was also a Victorian celebrity, a multi-media star of his day.
"Dickens was at the centre of a time when newspapers were becoming more and more available and the idea of the public persona interpreted by the media was just starting to happen. I think it was important to show his popularity, to show him as a public figure."
Who: Ralph Fiennes
What and when: The Grand Budapest Hotel (opens at cinemas Thursday); The Invisible Woman (opens at cinemas April 17)
- TimeOut