Patricia and Bernard Sparkes are offering a ''considerable'' part in the screen adaptation of their hit kid's book, 'Shelltown'.
The winner will attend rehearsals, voice a specially-created character, and receive two invites to the VIP post-filming party.
They will also pocket a two per cent share of Shelltown Production's royalties - estimated at between £50,000 and £70,000 per year - for life.
The sale began on internet auction site Humraz earlier this month, and will begin when all tickets - priced £5 - have been sold.
Profits will fund the show's #2.5 million production costs, and benefit three UK-based charities.
It will be the first time that a role has been sold to cover overheads, and could prompt other production companies to follow suit.
Bernard, co-director of Shelltown Productions, said the auction was a ''chance-in-a-lifetime'' for non-actors.
He said: ''This is an incredible, once-in-a-lifetime opportunity for ordinary people to appear in a classic TV programme.
''The winner will not only receive a considerable part alongside high-profile stars, but will also be given a significant royalty-share scheme in the Shelltown project.
''This is, then, a groundbreaking auction and one that could change the life of the winner forever.''
Mr Sparkes founded Shelltown in 1999 following the publication of his wife's children's books of the same name.
Patricia Sparkes, 50, penned a string of tales about 'Shelltown' for her 14 children as they were growing up.
Her stories follow the lives of three 'good eggs' called Splat, Cracker and Exactly, and their run-ins with the Bad Eggs Gang.
The Shelltown books proved such a success that the couple launched Shelltown Productions and funded a pilot animation.
Incredibly, the 4.5-minute pilot was spotted by Boyzone star Ronan Keating, who agreed to lend his voice to the lead character and write and perform the theme tune.
He was so impressed that he joined the company as a shareholder. Other stars have followed suit.
These include comedian Johnny Vegas, and the actors Ken Branagh, Julian Fellows and Irish comedian John Linehan.
Now the couple, from near Ballymoney are holding an online auction to raise the necessary funds to produce a series of 26, 10-minute episodes.
Entrants must purchase a 'seat' in the auction, but all bidding thereafter is free.
Tickets cost £5 but will rise over time - much like plane or rail tickets.
The auction will take place on internet site www.humraz.com when all seats have been sold.
The lucky winner will receive a part in the show, and a two per cent royalty share in Shelltown.
Profits from the contest will raise money for UNICEF, The National Autistic Society and the Marie Keating Foundation.
Mr Sparkes added: ''The cost of making 26 animated episodes is likely to be in the region of £2.5 million.
''As a small production company, we simply haven't got that kind of money - despite having major backing from some of Britain's biggest stars.
''That's why we've launched the auction - to raise production costs while giving people the chance to participate in something exciting and utterly unique.''
For more information about Shelltown, visit www.shelltown.co.uk. To take part in the auction, visit www.humraz.com