The cast for The Hitchhiker's Guide To The Galaxy - which is set to shoot at Elstree Studios in the UK from April - is rounding out.

Hip-hop star and actor Mos Def, Zooey Deschanel and The Office star Martin Freeman have all been confirmed for the Spyglass Entertainment/Walt Disney Co. project, a $50-$60m of adaptation of the sci-fi comedy epic by Douglas Adams.

It is being directed by Garth Jennings - one half of music video team Hammer & Tongs along with producer Nick Goldsmith.

Mos Def is set to play Ford Prefect, an alien disguised as a human who is stranded on earth before being thrust into interplanetary adventure with his friend, the tea drinking Englishman Arthur Dent (Freeman). The pair hitch a lift in space with the two-headed president of the galaxy, the beautiful scientist Trillion (Deschanel) and a depressed robot while on a quest to discover the meaning of life.

Love Actually star Bill Nighy is thought to be close to signing a deal to play alien planet designer Slartibartfast.

Galaxy executive producer Robbie Stamp - a long term friend and business colleague of Adams - told said that Freeman 'brought a contemporary edge' to the film.' He added: "When I saw his very first audition, the hairs on the back of my neck stood up. I thought here's Arthur. Here's an Arthur for 2005."

Douglas Adams died in 2001, having worked for many years to mount a big screen adaptation of his book. Stamp said that Douglas Adams' widow, Jane, "felt that one of the things that had to happen was a burst of young new energy was brought to the film - and that is reflected in the choices of Martin Freeland and Mos Def."

Graphics design company Shynola have been signed on to create the computer graphics for the electronic Guide in the film. Post-production for the film will take place in London, and deals are just being closed with a number of post-houses for the work.

The 12-16 week shoot will take place largely within the UK, and will include one or two foreign locations. It is set for release in the summer of 2005.

Galaxy is produced by Spyglass heads Roger Birnbaum and Gary Barber along with the company's Jon Glickman, filmmaker Jay Roach and Goldsmith. Derek Evans, Stamp and Adams will receive executive producer credits.

Mos Def appeared in Sundance festival hit The Woodsman, alongside Kevin Bacon. His other credits include The Italian Job and Monster's Ball.

Deschanel credits include Sundance film Eulogy, Elf, The Good Girl, All the Real Girls, Manic and Almost Famous.

As well as starring as one of Ricky Gervais' long suffering workers in The Office, Freeman has also appeared in Love Actually and Ali G Indahouse.