Actually. Penny and Leonard were dating “undercover”. It was in the part of the series where Leonard was fawning over her and she wasn’t interested. They kept it secret as they didn’t want reality to ruin the leonard chasing Penny part of the show.
Are you talking about the fact that the actress playing Penny and the actor playing Leonard were dating? I know abou that - it’s not relevant….I have no idea who these people are in real life, but there’s no way a “Penny” dates a “leonard” as portrayed on the show.
Apples and coconuts….