In Can You Ever Forgive Me? Grant plays Jack Hock, the fast-talking, hard-drinking sidekick to author Lee Israel (Melissa McCarthy) who is enlisted in her lucrative scheme forging and selling fake literary letters.
In real life, Hock was from Portland, Oregon, but Grant plays him as an aristocratic Englishman – “I would have loved to do it American, but the director didn’t want that” – and when he wrapped filming almost exactly a year ago, Grant says he hadn’t the faintest idea that an Oscar nomination was heading his way.
“You always hope that a movie’s just going to get released and seen, never mind this kind of response,” he says. “So, beyond what I think anyone could have predicted.
“I saw the first one when I was a 20-year-old drama student in 1977,” he explains, “So if you told me 41 years later I’d be in the final Star Wars, I would have said you were completely mad, it’s not possible. I was utterly astonished.”
“I hadn’t thought of it like that, but the character is just mine!” he laughs.
“I don’t know about the action figure or whether there will be one, but this is pretty amazing.”
And according to the actor we can expect some pretty big twists in the Skywalker saga’s last instalment, which he suggests will be pretty earth-shaking to fans of the franchise and well worth the series’ painstaking secrecy.
“Oh, it’s definitely worth it,” he says. “If you’re a Star Wars fan, and I am, then knowing what’s coming in this is quite something.
“I absolutely understand why they’re so secretive about it, because it’s very exciting.”
The film also offers the opportunity for a reunion between Grant and former Doctor Who star Matt Smith, who has also been confirmed to star in Star Wars IX around six years after the pair clashed as the Doctor and The Great Intelligence in the BBC sci-fi series.
“Yes, we were in a Christmas special and another episode together,” Grant says. But will they share any scenes again?
“I would be fired if I told you anything about that,” he smiles.
Between promoting Can You Ever Forgive Me? and making Star Wars, the rest of Grant’s year is looking pretty busy – he also played a recurring role in the latest run of Netflix’s A Series of Unfortunate Events – and he jokes that he’s later hoping to revive his role from the Spice World movie when the Spice Girls reunite on tour.
“Because Posh Spice isn’t doing the tour, I’m doing it,” he says, deadpan.
“Yeah, I’m going as Old Posh, Old Posh Spice. I’ve got the showgirl legs, so I’m going to be in the full regalia doing it.”
The only thing he isn’t looking forward to in the coming months? Having to watch his own performance, over and over again, on various awards-show highlight reels.
“It’s pretty excruciating,” he admits. “That’s the gruesome bit.
“But you have to get over yourself with that, because it’s only ego that makes you see all the things that you think are wrong or could be improved. And you’ve just got to accept what you see is not what other people see – hopefully.”
In the case of the Oscars’ selection body, we’d say that’s a point already proven.
Can You Ever Forgive Me? is released in UK cinemas on the 1st February
Sign up to the Radio Times newsletter for the latest TV and entertainment news