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Jim Parsons was so enthusiastic when discussing his upcoming “Big Bang Theory” prequel on Monday that he got somewhat tongue-tied.

Parsons spoke about “Young Sheldon,” which is headed to CBS this fall, at the Television Critics Association summer press tour.

The actor had a hard time putting in to words just what it felt like to have an entire spinoff series based on his loveably neurotic character, Sheldon Cooper.

“It was a moving experience to me to see something I’ve put a decade of my life toward [come to this],” Parsons said. “I never felt, in the 10 years that we worked on the ‘Big’ show, that …I can't talk! You don't think you're putting together these kinds of things that will add up to something like [a prequel].”

Iain Armitage plays young Sheldon, and Parsons revealed to Fox News he shared some advice with Armitage’s family once he noticed just how much buzz the series was getting.

Iain Armitage jim parsons ap

Iain Armitage, left, a cast member in the CBS series "Young Sheldon," and executive producer/narrator Jim Parsons take part in a panel discussion during the 2017 Television Critics Association Summer Press Tour on Tuesday, August 1, 2017, in Beverly Hills, Calif. (Chris Pizzello/Invision/AP)

“When I saw the marketing and all the posters with Iain’s face on them, I texted [Iain’s mom] immediately, ‘prepare.’”

He said of the Armitage family, “I think they are prepared.”

During the press panel, Parsons was asked if he was similar to the young Sheldon Cooper character, who is 9 on the series. The 44-year-old actor, who is gay, said he wasn’t much like Sheldon at that age.

“I didn't befuddle my parents -- that came much later with my sexuality,” he told reporters.

After 10 seasons of “The Big Bang Theory,” Parsons knows the ins-and-outs of playing the quirky Sheldon Cooper, and he said he was able to give Iain some advice about the brilliant, eccentric physicist he plays on “Big Bang.”

“One of the hardest things for someone like Iain playing the character is Iain is so empathic to other people and so in tune to other people’s needs and …those are great qualities to have, but in this particular character you almost have to let them play under the surface,” he said of Sheldon Cooper.

“Young Sheldon” premieres September 25th after the Season 11 premiere of “The Big Bang Theory” on CBS.