The actor is part of a star-studded cast in Sky’s new gritty series The Undoing.
The actor, 60, who stars in popular films including Notting Hill, Love Actually and Bridget Jones’s Diary, was speaking about his latest project, Sky Atlantic’s new six-part psychological thriller The Undoing.
He told The Graham Norton Show: “Having spent a career unable to muster a single emotion, I find in my old age I can’t stop them. It’s something to do with children or love, or my wife, or something, but I can’t keep it at bay.
“I did this job (The Undoing) partly to get away from my young children as they are exhausting at my age. I thought it would be great to have a break but every time I arrived in New York I missed them so badly I was a mess, so every scene was suddenly a cue for tears for me.
“I’d even go into a cafe and ask for a cup of coffee and the tears would come!.”
The father-of-five stars as Nicole Kidman’s husband in The Undoing alongside a cast which includes Donald Sutherland, Edgar Ramirez, Lily Rabe and Matilda De Angelis.
The script of the whodunnit thriller is penned by David E Kelley, the talent behind HBO series Big Little Lies, and is based on the novel You Should Have Known by Jean Hanff Korelitz.
Grant said of The Undoing: “It’s so hard to talk about because there are so many precipices and I don’t want to give anything away. But I can say I’m not the nice husband of Nicole Kidman that I have pretended to be.”
The actor also spoke about having Covid-19, which he says he had in the early days of the pandemic.
He told Norton: “I got it and I was very brave and manly about it! I got it right back at the beginning – I actually didn’t know what it was.
“It felt like mild flu and then a rather alarming complete loss of smell, which culminated in me sticking my head in dustbins sniffing, thinking, ‘There must be something here’ and spraying myself in the face with my wife’s Chanel No.5 but smelt nothing.”
Other stars appearing on The Graham Norton Show include Nigella Lawson, actresses Tina Fey and Amy Adams, comedian Romesh Ranganathan and singer Dua Lipa.
The Graham Norton Show airs on BBC One on Friday at 10.45pm.