The nine-year-old version of his character will be played by Iain Armitage.
Young Sheldon is expected to debut either later this year or early next year with a pilot episode directed by The Jungle Book's Jon Favreau.
Parsons will narrate the series, which has been compared to Malcolm in the Middle, with Zoe Perry, Lance Barber, Raegan Revord and Montana Jordan all set to appear.
It is unknown whether the child versions of other popular Big Bang Theory characters Leonard (Johnny Galecki), Penny (Kaley Cuoco), Howard (Simon Helberg) and Rajesh (Kunal Nayyar) will appear.
The five original cast members are said to be open to receiving a pay cut in order for co-stars Mayim Bialik (Amy) and Melissa Rauch (Bernadette) - who joined the show in its third season - to have a raise. The latter reportedly take home $200,000 (£160,000) compared to the original cast's $1 million (£800,000).
/The Independent/
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