“ What is a musical ?”

I heard the perpetual question raised again a few days ago, and not innocently or idly. A showbiz veteran was concerned about the prospects for “Tina: The Tina Turner Musical,” which opened on Thursday at the Lunt-Fontanne Theater.

How would it be different from a rock concert? she wondered. Would a life story like Turner’s fit into the form? And why, she asked finally, “would anyone want to see that?”

These are great questions, which is not surprising because the person asking them was Tina Turner herself. Now happily retired, and turning 80 this month , she discussed her initial misgivings in an article she recently wrote for Rolling Stone about the making of the $16.5 million bio-jukebox musical that now bears her name. Apparently, she got over her doubts; is it unfriendly to say that, having seen the show, I’m still working on mine?

And make no mistake, I see Turner — the greatest rock queen ever to drag herself onto her own damn throne — as a friend, at least in the sense that millions of others do, as someone to admire and even protect. If hers has been the story of triumph rescued from the disaster of childhood neglect and horrendous spousal abuse, ours has been the good fortune to see that redemption rendered in real time as music and spectacle.