JUST when it seemed that no one could challenge the computer animated might of Pixar (Ratatouille, WALL-E), directors Rob Letterman and Conrad Vernon deliver an out-of-this-world adventure which proves heroes come in all shapes and sizes.

Fast-paced and peppered with cute visual gags, Monsters Vs Aliens is a blast from eye-popping start to uproarious finish, especially in cinemas projecting in jaw-dropping 3D.

Admittedly, Letterman and Vernon's picture borrows heavily from Pixar's 2004 smash hit The Incredibles, with nods to Godzilla and countless B-movies, but there are sufficient flashes of invention and a smattering of heartfelt emotion to bring a tear to the eye.

The opening section delivers one wow moment after the next as the camera drifts through space towards Earth, descending on a research facility where a scientist plays with an elasticated bat and ball (which appears to bounce out of the screen in 3D), just as an unidentified flying object hurtles towards California.

The object – a green, glowing meteorite – lands on fun-loving Susan Murphy (voiced by Reese Witherspoon) on her wedding day, shortly before she is due to tie the knot to TV weatherman Derek Dietl (Paul Rudd).

Before he has a chance to say I do. Susan grows in size until she stands an impressive 49ft and 11ins tall.

Wedding guests flee and Susan is held hostage by the military in a secret government compound where she learns that other so-called monsters have suffered a similar fate.