The ball of fluff grows up to become Krypto the Superdog (voiced by Dwayne “Not Him Again” Johnson), Superman’s crime-fighting wingman and best mate.

Krypto has the same superpowers as his master (flight, X-ray vision, laser eyes) and boasts a similar pair of miraculous, identity-concealing specs.

But their bond is tested when a nervous Superman (John Krasinski) prepares to propose to reporter Lois Lane (Olivia Wilde).

Krypto is so busy whining about the prospect of being relegated from the bed to the couch, he doesn’t notice his master is in trouble. Along with the rest of the Justice League, Superman has been kidnapped by a guinea pig.

They say a film is only as good as its villain, and evil, hairless Lulu (an enjoyably hammy Kate McKinnon) saves this patchy comedy.

A former associate of Lex Luthor, she’s been trapped in an animal shelter and harnessing the power of “orange kryptonite,” a space rock that bestows pets with superpowers.

But the rock also powers up her fellow prisoners – Ace the hound (Kevin Hart), pig PB (Vanessa Bayer), Merton the turtle (Natasha Lyonne) and squirrel Chip (Diego Luna).

When Krypto loses his powers, he must turn to these rookie superheroes for help.

The plot is predictable and the pet-based gags are a little creaky. As with the far funnier Lego Batman movie, the sharpest jokes are aimed at accompanying adults.

“Batman works alone,” growls Keanu Reeves’ Caped Crusader. “Except for Robin. And Gordon. And Alfred… and whoever Morgan Freeman played.”

• DC League Of Super-Pets, Cert PG, In cinemas now