You don’t mess with the master. Don’t even think about singing “Respect.” Aretha did it, and you’ll only do it worse. “My Girl”? Forget about it. The Temptations did it; your effort won’t compare. “Over the Rainbow”? Not even The Genius himself, Ray Charles, could match Judy Garland.

But once in a while, someone pulls it off. Ray gave us a perfect song, “Georgia on My Mind.” Put it on a loop. Let it play forever. But Willie Nelson’s version is worthy of comparison. Sometimes, if you’re brilliant — and Willie is brilliant — you can take a perfect song and still make it yours.

Last night, on “The Voice,” the four judges — Shakira, Adam Levine, Blake Shelton and Usher — tackled Lennon-McCartney’s “A Little Help From My Friends.”

And they killed it. Hit it right out of the park.

But here’s what struck me . . .

“A Little Help From My Friends” is a pop song, a cute little ditty from the Beatles’ Sgt. Pepper’s Album.

It’s a wonderful song, from possibly the greatest album of all time. But it’s not the defining version of the song. The defining version, the one against which you match all challengers, was done by Joe Cocker.

The first time we heard Cocker’s version, it spun our heads around. Cocker took on the master, and he slayed him. THIS was how it should be done. Cocker took a song from Sgt. Pepper’s and he made it his. If you want to mess with the master, you mess with Cocker — not the Beatles — on this one.

So kudos to the Voice judges for doing it right, and kudos to Joe Cocker for showing us all how a great song by the greatest group of all time can be done even greater.

And happy 71st birthday to Paul McCartney. Only wish John and George were around to help you celebrate.