The Big Bang Theory ended Season 10 in shocking fashion, with Sheldon bowing down on one knee and asking Amy to be his wife.

It was the mother of all cliffhangers, and while the cast appeared at San Diego Comic-Con, it was evident they were sworn to secrecy and tried to dodge questions about it at every turn.

That's not to say the panel was dull by any means. The cast of the CBS juggernaut is just as engaging in real life as their characters.

The proposal was such a big scene for the cast and crew. It was years in the making. There was always a time Sheldon was going to have to grow up, and he chose it wisely.

“I started crying,” Kaley Cuoco said.

“We were all crying, watching them do it,” cast member, Kunal Nayyar said.

“I came as close to crying as is possible for me,” added fellow co-star Johnny Galecki.

“To see that be the pinnacle of this season was really cool,” Cuoco said. “We’ve all come such a long way.”

The cast then went on to talk about some of their favorite guest stars. Showrunner Steve Molaro had a special shout out for the late Adam West.

“He had a line in the script where he told Leonard and Koothrappali, ‘Don’t ring my doorbell or my poodles will go crazy,'” Molaro revealed.

West even asked if his character could have a stronger dog, “like a Rottweiler.” When Molaro revealed that a poodle would be more comical, West said, “Well, I have poodles in real life, so I guess it’s fine.”

Executive producer Steve Holland remembered the time James Earl Jones and Carrie Fisher met on set during filming for a guest stint.

That was actually the first time the Star Wars stars ever crossed paths.

“She came out, and she said ‘Dad!’ and then they hugged,” Holland said, smiling.

Talk then turned to Penny's maiden name when one fan asked Penny if she had any idea what it was. It has never been revealed on the series, so fans have long speculated what it could be.

“I have it in my head what I think what it is,” the actress said. “But now I’m Penny Hofstadter, so it doesn’t matter.”

Ugh, it does matter. But we bet it becomes one of those things that will still be asked years after the series concludes.

The fun panel concluded with what Molaro called a “never-before-seen version of ‘Soft Kitty'” singalong. Alternate lyrics: "Soft bunny, warm bunny, floppy ears on top, happy bunny, sleepy bunny, hop, hop, hop” and “Hard turtle, wet turtle, where did your head go? Happy turtle, sleepy turtle, slow, slow, slow.”