They really were “on a mission from God.”

In a stunning move by the Vatican, the classic Dan Aykroyd-John Belushi comedy film “The Blues Brothers” was declared a “Catholic classic” alongside more pious films such as “The Ten Commandments” and “The Passion of the Christ.”

The announcement was made in the Vatican’s official newspaper L’Osservatore Romano, corresponding with 30th anniversary of the release of the film.

“As a former altar boy from age 6 . . . but a somewhat lapsed Catholic, I was delighted with the endorsement,” Aykroyd said in a message to The Post yesterday.

“My local monsignor will immediately be receiving a check for parish needs.”

L’Osservatore editor Gian Maria Vian praised the flick for its plot, in which Jake Blues (Belushi) and his brother Elwood (Aykroyd) battle cops, neo-Nazis and crazed country fans in a bid to save the Catholic orphanage where they were raised.

“For them, this Catholic institution is their only family,” Vian wrote. “And they decide to save it at any cost.”

L’Osservatore’s editorial lavishes praise on the 1980 comic romp, in which Aykroyd and Belushi say that they’re “on a mission from God.” The writers call it “incredibly shrewd” noting that in one scene a picture of Pope John Paul II could clearly be seen.