A new episode of The Simpsons is to premiere in the UK for the first time

Hit animated comedy The Simpsons is celebrating its 20th anniversary with a competition to create a new character.

The new Springfield resident will appear in an early 2010 episode, also featuring Coldplay's Chris Martin.

The contest, open for just one week, promises the winner a trip to Los Angeles to work with the show's producers and the animation director.

Submissions should be "pithy and funny" with a "typical Simpsons overbite", said executive producer Al Jean.

"It's gotta be a human being. We've narrowed it down that much," he added.

Jean, who will judge the online contest with Simpsons creator Matt Groening, said the competition was a form of thank-you to the show's enduring fanbase.

Prime-time history

The Simpsons is set to become the longest-running prime-time series in US TV history after makers Fox ordered another two seasons.

"We're now in uncharted waters: We've gone longer than any scripted show in prime-time history," said Jean.

"It's a cliche, but it wouldn't be so except for these people who've loved the show all these years."

The episode featuring the new character will see Homer disappoint wife Marge by arriving late at a wedding after stopping to buy a lottery ticket.

He encounters the new face while rushing to the ceremony, Jean said, adding that it's possible the character may return in another episode.

The Simpsons was first shown in December 1989, and made its UK debut on Sky in September 1990.

The new commission of 44 episodes over two seasons will bring the total number of shows to 493.

The cartoon, featuring Bart, Homer, Marge and other residents of Springfield, has received 24 Emmy awards in its 20 years on screen.