The Tweenies are very popular worldwide

The show - starring Milo, Jake, Bella and Fizz - is to be made into a full-length movie.

The BBC show featuring the brightly coloured characters has been a hit in 70 countries, generating sales worth millions of pounds.

The movie, which will be co-produced by Tell Tale Productions, which makes the TV show, is due to be released in the summer of 2005.

Hit record

Helen Cadwallader, from Tell Tale, told BBC News Online the film was in pre-production.

She said: "It will take the Tweenies out of their present environment and into fairyland."

The film is being co-produced by Tell Tale Films, Spice Factory and UK tax fund Movision, which will also co-finance.

A merchandising phenomenon to rival the Teletubbies, the Tweenies have sold more than three million videos in Britain alone and have even scored a Top 10 hit single.

Television company Nickelodeon recently bought the rights to broadcast the show in the US.