Martin Scorsese needs to de-age me now that I’ve seen “The Irishman,” his epic that had its world premiere Friday at the New York Film Festival.

At 3 ¹/₂ hours, the Frank Sheeran-Jimmy Hoffa biopic is not only the longest film of Scorsese’s career, but the longest studio movie of the decade.

Well, chug a 5-hour Energy, because the terrific “Irishman” deserves your full, un-fatigued attention.

The buzz around the movie until now has not been about how this is Scorsese’s first collaboration with Al Pacino, or that it’s the director’s grand return to the mafia genre after 1995’s “Casino.” What the people are going crazy over are the digital face-lifts. That’s right — Robert De Niro, Joe Pesci and Pacino are given the Joan Rivers treatment with the help of CGI.

We watch Sheeran (De Niro), a truck-driver-turned-mob-fixer age back-and-forth from his 30s to his 80s and many years in between. The pricey special effect is cool, if occasionally creepy. In the youthful scenes, De Niro looks less 30 and more Gumby, with expressionless eyes and face only a Martian could love. But as the actors move closer to their natural ages, the subtle, computerized wrinkle cream works wonders.

The first part of the movie is a lot like “Goodfellas.” There’s voiceover narration provided by Sheeran from a retirement home and a nostalgic origin story set to “In the Still of the Night.” He starts off in the 1950s as a union driver and soon winds up doing favors for the Pennsylvania-based Bufalino crime family, headed by Russell Bufalino (Pesci).

Pesci’s iconic turns are so rammed in our minds that it’s easy to forget he retired and hasn’t made a movie in almost a decade. But in this genre, Pesci’s the Most Valuable Paisan. The 76-year-old actor brings all his scrappy idiosyncrasies, but is also more tender and introspective than usual.

“The Irishman” breaks from the mobster flick formula when Hoffa (Pacino) enters the picture in the 1960s. A pal of the Bufalinos, the powerful union boss needs protection, so they enlist Sheeran. The pair become friends, and the fixer’s questions of loyalty, love and family intensify.

This has a different tone than your average gangster film. Plenty of marks are shot in the forehead, yes, and a lot of wine is poured in the corner booths of dimly lit Italian restaurants, but it’s also knock-down, drag-out-into-the-river funny. The best line belongs to De Niro: “Usually three people can keep a secret,” he says. “When two of them are dead.” And Pacino is a ham as Hoffa, wildly gesturing like a coked-up cheerleader and bickering with everybody.

Speaking of Jimmy, the movie is based on the 2004 biography of Sheeran called “I Heard You Paint Houses,” and so we see his version of what happened to Hoffa, who went missing in 1975 and was never found. I won’t tell you what that story is, but it sure ain’t vague.

Five decades is a lot of history to hold together, and it could have easily crumbled. Remember “Gotti”? But Scorsese is at the top of his game here. His film is never boring, and it explores some unexpectedly deep themes for mafiosos. Witness De Niro coming alive as his character crawls toward death: friendless, ailing and with only a priest to talk to.

The director’s mindset has, thankfully, not been de-aged. When Scorsese was 47, he made a movie in which his main character said he “always wanted to be a gangster.” At 76, Scorsese would rather focus on a guy who just wants his daughter to call back.