11/29/2012 10:29 am ET Updated Nov 29, 2012

'Big Bang Theory': Kaley Cuoco Talks 'I Love You' Scene With Johnny Galecki

It finally happened: Penny (Kaley Cuoco) told Leonard (Johnny Galecki) that she loved him on "The Big Bang Theory" (Thursdays at 8 p.m. EST on CBS).

And while it was an emotional scene for viewers, it wasn't easy for Cuoco either.

"I cried at the table read. I cried in the rehearsal. I cried in run-throughs," Cuoco told TVLine. "That’s why I had to take such a long beat, because I thought, 'If I close my eyes, tears are just going to come streaming down my face,' and I wanted it to look more pent-up. I thought, 'Oh, they’ll tighten that [in editing],' but they left it all in there. I guess they liked it."

There's no doubt that viewers liked it, especially because so many of them tuned in.

The show -- which is currently in its sixth season -- racked in 17.6 million viewers on November 15, making it the series' most watched episode ever.

The show's success may have something to do with the direction the producers have taken the characters. According to Cuoco, that's what makes them so lovable.

"[Penny] is street smart and good-hearted and can make fun of herself," Cuoco told the Associated Press. "The producers never made her ditzy. Maybe she doesn't always get what the guys are talking about. But in that way she represents most of the world."

"The Big Bang Theory" airs on Thursdays at 8 p.m. EST on CBS.

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