Johnny Galecki made a frank confession regarding his return to 'Roseanne'

Johnny Galecki might be most well known for his role as Leonard Hofstadter from The Big Bang Theory, but he started his acting career in the sitcom Roseanne.

Please note this article contains spoilers.

The 43-year-old Galecki wasn't part of the original plans for the show's revival and only made a surprise appearance mid-way through season 10 in Darlene vs. David.

Galecki initially joined the cast in 1992 as Darlene's shy high school sweetheart. In an interview with People, he revealed that it was a 'personal experience,' to return two decades later.

He said that filming the Darlene vs. David episode was a wonderful yet emotional week for the entire crew. The subject matter of the episode brought back memories.

'Apart from being born, possibly the most surreal experience of my life. Deep thanks to my Big Bang Theory family for knowing the importance of visiting one’s roots and loaning me out for a quick minute.'

Johnny Galecki, Instagram, December 2, 2017.

Fans already learned that Darlene and David divorced at some point before the events of the show. Darlene and their two children moved back in with Roseanne and Dan.

In episode four, David 'pays an unexpected visit' to Darlene and the couple attempt to reconcile. Their characters also reminisce about the past, and Galecki said the experience was surreal.

David had 'been dormant for 21 years in the inner folds of [his] psyche,' and Galecki was surprised how easy it was to step into the character's shoes again.

Keeping in touch which his co-stars throughout the years also made it easier for Galecki to bring David to fore again, Inquisitr reported.

Sara Gilbert, who portrays Darlene, and Laurie Metcalf who reprised the role of Roseanne's sister Jackie, both appeared in The Big Bang Theory alongside Galecki.

He also kept in touch with Roseanne Barr throughout the years but admits it is Gilbert and Metcalf who he has the strongest bond with.