Richard E. Grant braved a paralyzingly cold night last week to attend a screening of "Withnail & I," his cultishly adored film debut, in the midst of a whirlwind and much-enjoyed campaign for his Oscar-nominated turn in "Can You Ever Forgive Me?"

That it was frigid was fitting. Grant and his co-star, Paul McGann, both playing hopelessly out-of-work actors, spend much of 1987's "Withnail & I" either freezing, hungry or, most of all, desperate for a drink. "It's like Greenland in here," Grant's Withnail says. "We've got to get some booze."

If "Withnail" captured the lowest of ebbs for an actor, Grant is, 33 years later, riding the ultimate high. Once again, it's for playing, as he says, "an alcoholic in a long coat" in a movie about friendship and failure. Grant is nominated for best supporting actor for his Jack Hock in Marielle Heller's 1990s New York drama. Hock is an old acquaintance of biographer Lee Israel (Melissa McCarthy) who, shortly before she turns to forgery, is befriended by Hock in a bar. "This and that," he summarizes his doings in the lean, intervening years. "Mostly that."

But much more than it has for his characters, fortune is smiling on Grant. Even on a dark, cold night, he was aglow with a spotlight that has seldom found him.

"People on the street smile at you in a way I've never experienced before," said Grant, with a scarf tucked snuggly around his neck, in an interview before the screening at the Manhattan repertory sanctuary, the Film Forum. "I was walking around SoHo, and even in this blistering minus-15 degree cold, I've seen very friendly faces looking toward me. I now accept that they're looking at me rather than looking over my shoulder at someone else. That's a delight."

Grant's swooning reactions to his Golden Globes and Oscars nominations have gone viral, as has his social-media exchange with his childhood idol, Barbra Streisand. As a 14-year-old growing up in Swaziland, Grant wrote Streisand a letter offering her a two-week holiday "respite" in the tiny African country. Photographs captured him tearing up when Streisand responded on Twitter.

"I know it's something you're supposed to get over, these teenage obsessions, when you become an adult," says Grant. "But clearly I have the maturity of somebody who's 17."

Grant, 61, has spent a journeyman, character actor's career oozing a gentlemanly charm that often only thinly masks an eye-popping mania. In his second, surreal collaboration with "Withnail" director Bruce Greenfield, "How to Get Ahead in Advertising," he played an ad executive who, in the throes of a nervous breakdown, grows a talking boil.

A kind of revival was kicked off for Grant a few years ago in a recurring role on Lena Dunham's "Girls" and Richard Shepard's "Dom Hemingway." He has a part in the upcoming "Star Wars" movie. But the only award Grant ever recalls being nominated before was a Razzie (for 1991's "Hudson Hawk"). So lately, he's been "floating on a hovercraft of disbelief" — even if he recognizes the sensation is ephemeral. (He's convinced Mahershala Ali will win the Oscar in his category.)

"You shoot a movie for 26 days and then you're on a promotional awards trail, as they call it, for five months, and you don't earn any money doing that. But for me it's a once-in-a-lifetime thing," says Grant. "Yet come February 24 when Mahershala wins, it will be gone, cheers, tumbleweed."