US network CBS revealed a five-minute glimpse at Young Sheldon at their Upfronts presentation in New York on Thursday.

The series, a prequel to Seven's hit sitcom, follows Jim Parsons' series favourite Sheldon Cooper at nine years old, as the misfit genius struggles to cope with skipping a few grades and being bumped straight into high school.

Although the series sports a voiceover narration from Parsons - who has earned four Emmy Awards (and countless millions) playing the role for almost a decade - young Sheldon is played by Iain Armitage, who recently starred as Ziggy Chapman in the HBO hit Big Little Lies.

The unlikely spinoff was met with mockery ahead of CBS's confirmed announcement in March, with online detractors facetiously labelling the project "Sheldon: The Wonder Years", but the trailer seems promising enough.

A heartwarming scene, featuring Sheldon saying grace at the dinner table with his boisterous family - a gang of football-loving, religiously devout, brash Texans - hints at a more sentimental tone than its gag-heavy predecessor.

"It's like an origin story. We had this idea about my little nephew, who is really smart, down in Texas," Parsons recently explained on Watch What Happens Live, discussing the personal project.

"My family is pretty average - no offence to them, but they're very normal and he's very smart. One thing led to another and I thought, 'This could be Sheldon.'" he said.

Parsons and his Big Bang crew recently secured two more seasons of the hit show, even agreeing to take a slight cut to their $US1 million-per-episode paycheques so their lesser-paid co-stars could get a raise.

Young Sheldon is due to premiere in the US in September, with a local broadcaster yet to be confirmed.