Tobey Maguire is worried film goers will not be able to understand the plot of the new Spider-Man movie.

The actor, who reprises his role as the web-slinging superhero in the third instalment of the hugely successful series, believes the storyline may be too complex for fans unfamiliar with the comic books.

In the movie, Spider-Man battles Venom - a symbiote which in the Marvel comic universe is an alien life-form that bonds with other living organisms to survive.

After bonding with the superhero, whose alter-ego is Peter Parker, the symbiote gains Spider-Man's special powers.

Tobey said: "I know a lot of fans might not have heard of him. Basically, there's the goo, right? The symbiote, dark energy, is the goo that creates Venom."

Spider-Man also takes on super-villains Sandman, played by Thomas Haden Church, and The New Goblin, played by James Franco.

The eagerly awaited new film is due for release in the summer of 2007.