The boxing ring and the comedy stage both have painful karma in common — when you bomb it can be a literal and metaphorical punch in the guts.

Last year, British fighter Ricky Hatton, a beloved hero to his hometown fans of Manchester, in the north of England, endured the literal form when he was knocked out cold in Las Vegas by Manny Pacquiao’s fists of fury.

Ringside were the usual showbiz suspects — and next to P Diddy, who jumped off his chair when Hatton hit the deck in the second round, was outrageous British stand-up comedian and actor Russell Brand.

The emerging film star was getting to know the music/fashion/perfume/vodka mogul for their dual star turns in the Judd Apatow-produced comedy, “Get Him to the Greek.”

In the film, Brand, who like any successful stand-up comic must have taken quite a few metaphorical punches, reprises his “Forgetting Sarah Marshall” role as self-styled rock god Aldous Snow, whom fellow “Marshall’” alum Jonah Hill, playing lowly record company executive Aaron Green, has to deliver to Los Angeles’ Greek Theater for a lucrative revival concert.

The mission is ordered by Green’s clownish, hyperactive record boss, Sergio Roma (P Diddy), who critics — this one included — were probably sharpening their quills to tear asunder, but delivers a riotous, rendition of mock self-importance.

But it’s the lanky, long-haired, London-born comic who steals the show.

And Brand, famous here for the his aforementioned first outing as Snow, his 2009 risqué hosting of the MTV Video Music Music Awards where he mocked the Jonas Brothers’ virginity pledge and being engaged to “I Kissed a Girl” pop star Katy Perry, has already led quite the rock-and-roll life.

Across the pond, art imitated life, as Brand’s notorious party monster lifestyle spiraled into a haze of alcohol and drugs, while he became a tabloid dream for bedding every model and TV actress he could get his hands on.

Implosion was imminent, and when he and fellow media personality Jonathan Ross made an X-rated crank call to one of Brand’s ex-girlfriend’s, the daughter of renowned actor Andrew Sachs, everything hit the fan and public outrage resulted in his resignation from BBC Radio.

To his credit, Brand did get clean and sober — and by all accounts, including his own, cannot wait to walk down the aisle.

However, he still has tons of that cockney wit, which he has been displaying on a long promotional tour for the movie, first in London, then Vegas and last week at The Greek, which May 25 hosted a star-studded premiere.

For instance, in recalling his first meeting with Diddy, did they bond over Faust or go for a good old pint?

“No there wasn’t a Faustian discussion, but there was an immediate Faustian pact, where Puff took me and Jonah individually to Vegas,” said Brand.

Here for the purposes of transatlantic humor, one should note that the North/South rivalry in England is much like the East/West Coast beef.

“Ricky was fighting Pacquiao and Puff asked me to get us some tickets. And when Puffy asks you something, it makes you wanna say yes. I got Ricky’s cell number, but it was two days before the fight and I guess he was busy. But in the end one of me mates came through.”

He added: “So there’s Ricky, bless him, a folk hero, on the deck and Puffy jumps on a chair with like 25,000 Mancs [Manchester folk] in the room. Well, I was a bit self-conscious. Jay-Z’s here, Puffy’s there, jumping out of his chair, Ricky’s on the floor, I’m here and there’s 25,000 Mancs. That was not a good look.”

Nevertheless, channeling his inner rock muse came naturally to Brand, especially with his coterie of famous mates from the music scene.

“I do hang out with rock stars, just ‘cause they’re my friends,” he said. “Noel Gallagher (Oasis), Pete Doherty (Babyshambles), [Amy] Winehouse, she’s me mate and Car Barât (The Libertines), he’s on the soundtrack.

“From Noel, I learned this inherent, rock nonchalance. So I asked him one day, ‘Noel, where do you get this nonchalance, then?’

“And he said, ‘I know that anywhere I go, no matter what people say about me, as long as I’ve got the guitar and the ability to play it, people will pay ten quid to see me.’ [Well,] Aldous knows that people will pay him money for his gift, whereas comedians, we tend to be more neurotic about that stuff.”

With his Greek gig, two big animated movies coming out later in the year, a sequel to his best-selling writing debut, “My Booky Wook: A Memoir of Sex, Drugs and Stand-Up,” called “My Booky 2: This Time It’s Personal,” Brand doesn’t seem to have much to be worried about.

In fact, next month he’ll be moving to New York to take on the role one of his comic heroes, Dudley Moore, made famous in “Arthur.”

“The love interest will be reprised by Liza Minnelli,” he cracked, “and I’m gonna turn her spine to chalk.”