He found fame in The English Patient before becoming a huge TV star. Now he is tackling the Theranos fraud scandal. But addiction in the 90s nearly cost him everything

If your abiding image of Naveen Andrews is as Sayid from Lost – the soulful Iraqi officer whose sad eyes, powerful biceps and luxuriant hair set many mid-00s hearts a-flutter – you might be in for a shock seeing him in The Dropout. Paunchy, bespectacled, greying, with shockingly normal-length hair, he is less a strapping man of action and more a middle-aged man of business – and not a very good one at that. Andrews portrays Sunny Balwani, the partner and alleged co-conspirator of Elizabeth Holmes, who was once the world’s youngest female billionaire and is now a convicted corporate fraudster.

On a video call from his home in Santa Monica, California, Andrews, 53, looks more Sayid than Sunny. His black gym vest exposes reassuringly well-toned biceps; the hair is returning to its trademark resplendence. He gained 9kg (1st 6lb) for The Dropout, he explains, to make his face fuller and his belly paunchier. He also modified his movements to seem slower and older. “Well, I did at least want to resemble the character I was playing,” he says, a little sting of sarcasm in his inflection.