At this point in George Takei’s thoroughly lived life, his bucket list is pretty short.

From his Hollywood career, most notably playing Enterprise helmsman Sulu on “Star Trek,” to his gay-rights activism to his accidental reincarnation as the King of Facebook, the 77-year-old dynamo who still does 50 situps and 100 push-ups every morning has accomplished as much as any mortal could hope for. Except maybe creating and starring in a Broadway musical.

Now he can scratch that one off, too. This fall, Takei’s “Allegiance,” a musical inspired by his childhood experience living in Japanese-American internment camps during World War II, opens on Broadway.

Takei, who appears March 5 and 6 at the Guthrie on the American Public Media variety show “Wits,” can be as funny and tart-tongued as any guest of the series. But he’s passionately serious on the topic of those camps, where at age 5 he was incarcerated with his family, as were most Americans of Japanese descent following unfair suspicions of disloyalty raised after Pearl Harbor. It’s tough to get him off the subject, in fact. But he’s the terminally likable George Takei, so that’s OK.

“I remember the barbed wire, the guards with their machine guns looking down from the sentry towers, the searchlights that followed me on my night runs to the latrine. And every morning in the tar-papered barracks where we had school, I put my hand on my heart and recited the Pledge of Allegiance — ‘with liberty and justice for all.’ ”

How, exactly, are he and his collaborators making a musical out of that?

“People guffaw, but actually it’s a lovely story about the resiliency of people, their ability to find joy even in such circumstances,” he said. “There are two beautiful and dangerous love stories. A majority of people know very little about this shameful part of American history, and there’s no better way to reach them than through music from the heart.”

It was his desire to drum up awareness of and support for his musical that led Takei to begin experimenting online with social media seven years ago.

“We needed to build an audience, so I thought, let’s see how we can use this technology,” he said. “At that point my fan base was mostly sci-fi geeks and nerds, so I started with them, making note of what kinds of posts got the most likes, and of course it was anything with humor, and in particular Grumpy Cat.”

He continued, “As my audience grew more diverse I started interjecting social justice advocacy and commentaries about LGBT equality, and it just kept growing more.”

Veto caused him to come out

His droll geniality and quirky postings on Facebook, Twitter and Instagram have earned him 5.5 million online fans, many of whom are no more than a quarter of his age. He also has developed some improbable relationships, notably with shock jock Howard Stern, on whose radio show he has appeared many times. He chuckled while remembering his first Stern encounter.

“I was doing an off-Broadway play in New York, and had to make the rounds promoting it,” he said. “I just went from address to address and found myself in a waiting room on Madison Avenue. They had the radio tuned to the most crass, disgusting conversation, and I said to the guy next to me, ‘Why can’t they play some nice music?’ He said, ‘That’s the show we’re going on.’ Then I go into the studio and here’s this skinny bespectacled wild-haired guy. … He kept calling me back. It is kind of strenuous doing that show.”

In addition to writing an autobiography and a book on his Internet fame and being the subject of the 2014 documentary film “To Be Takei,” he and his husband, Brad, were the first gay couple to appear on “The Newlywed Game,” in 2009. Naturally, they won, because “we’d been together for 20 years already, and knew everything that was in each other’s closets pretty well,” Takei said.

Speaking of closets, Takei kept his sexual orientation private for most of his Hollywood years, because he’d seen other gay actors’ careers ruined in the 1960s and ’70s. But in 2005, the actions of an actor turned governor of California finally brought him out.

“When Arnold Schwarzenegger vetoed the same-sex marriage bill, my blood was boiling,” Takei recalled. “I had been silent, but that night Brad and I watched the news and saw all these young people pouring out on Santa Monica Boulevard venting their rage and I said, ‘I have to speak out.’ ”

Memories of Minneapolis

The last time Takei performed in Minneapolis was to do a sci-fi narration, “To Boldly Go,” in his sonorous bass voice with the Minnesota Orchestra.

“I love how your buildings downtown are all connected by little bridges,” he said. “Your city fathers showed foresight and eminent good sense.”

Although social media status can be hot one minute and not the next, Takei’s popularity shows no sign of flagging. One indication: Last Friday, on hearing the news of the death of his “Star Trek” co-star Leonard Nimoy, Takei wrote on Facebook, “Today, the world lost a great man, and I lost a great friend. We return you now to the stars, Leonard. You taught us to ‘Live Long And Prosper,’ and you indeed did, friend. I shall miss you in so many, many ways.”

Within one hour, the post had been liked by nearly 480,000 people.