He said she laughed when she heard the pitch but was absolutely on board to take part in the spin-off series.
Penny was one of the best-loved characters in the series and formed an unlikely relationship with genius Leonard (Johnny Galecki).
In The Big Bang Theory she was an aspiring actress who was always trying to find ways to catch her big break.
Fans have been revisiting the series to reminisce about her character and her co-stars.
New episodes of Young Sheldon air on Thursdays at 8pm on CBS, and episodes are available to watch on All4 in the UK
