The concept for 100th episode of The Big Bang Theory — in which Leonard (Johnny Galecki) and Penny (Kaley Cuoco) reunite
Lorre’s initial intention, Prady tells The Hollywood Reporter, was to bring the show full circle back to the pilot and tell a dual what-if dream story exploring what their lives could have been like if Leonard had asked Penny out upon meeting her when she first moved in across the hall.
The result was “The Recombination Hypothesis,” a unique installment in which it’s revealed late in the episode that the on-again/off-again couple’s reunion took place in Leonard’s mind — until, that is, he turns it into a reality and asks Penny out on an actual date, thus reuniting the couple.
It’s a moment that the EPs say was scripted carefully so as not to tease fans, noting the original plan was to cut to a commercial immediately after it was revealed the reunion was entirely in Leonard’s imagination before coming back to see the lovable nerd really asking her out. “Our feeling was no, he’s got to go immediately,” Prady says. “In the same moment that the audience is going, ‘Oh my God, that didn’t happen,” we have to say, ‘Yes, but this is.’ ”