The story of an unwanted pregnancy doesn't sound like it would make for a cracking comedy - but that is exactly what Knocked Up is.

The last thing 24-year-old up-and-coming TV presenter Allison Scott wanted to do was get pregnant - and least of all to beer-bellied slacker Ben Stone.

Click here to see Knocked Up trailer.

So when Allison (Katherine Heigl) celebrates her recent promotion at work and winds up having a drunken one-night stand with Ben (Seth Rogen), she is faced with an unwanted pregnancy, and makes the tough decision to give Ben a chance to get to know her and see if they might be able to make a go of it for the sake of the baby.

But of course Ben is the overgrown kid who has no desire to settle down, and would rather spend his time counting the length of time female actors spend naked in every film and cataloging it for a new website.

Of course what follows is nine months of pure hilarity and sentimentality as the couple try and make things work between them, and get to grips with the fact they are having a child.

This film is by far the best comedy of the year, and it should be, as writer and director Judd Apatow created the hugely successful 40-year-old Virgin.

Watching Ben struggle to give up his weed and his bong, and branch out of the house he shares with his like minded friends is a joy to watch, and the sentimental moments are heart-melting.

By far the funniest part is too rude to mention, but anyone who watches the film is sure to agree.

The script is in the main, pure gold, with some belting lines coming from the assistant to Allison's boss who's stony face and one-liners make for some proper belly laughs.

The story and characters are developed in such a way that everyone will be able to relate in some way to their fears and anxieties, and the sub-plot with Allison' sister and her husband also plays a key role in the film.

The film is packed full of cracking jokes and lovely sentimental moments, and is finished off superbly with a montage of the cast and crews' baby photos.

A definite must-see for all comedy lovers.

Click here for Knocked Up showtimes at Odeon Silverlink.