Kaley Cuoco needed stitches after a prank went wrong on the set of 'The Big Bang Theory'.

Kaley Cuoco

Kaley Cuoco

The blonde beauty wanted to turn a dinner fight scene between her character and Johnny Galecki's character into a bigger event to prank the rest of the cast and crew but it backfired when she ended up hitting her head hard.

Speaking at San Diego Comic Con, she said: "We thought it would be really funny for the gag reel to take it really far. We did it. [When I got up] all I see is blood gushing out of my head ... it was all over me!

"I had to get stitches that day and come shoot the next day. I got back and there were signs that said, 'No fun allowed on the Big Bang set.'"

It comes after Kaley, 31, revealed she overcame her fear of bungee jumping so she could impress her boyfriend Karl Cook's parents.

She recalled: "My boyfriend's family took me on a vacation to New Zealand for New Year's, which is the nicest, most amazing thing in the world. They're like, daredevils. My boyfriend is a daredevil, he loves to do all [that] stuff. So he told me, 'We're so excited! Midweek we're going to go on a canyon swing!' And I'm like, 'Well that sounds like fun, I like a swing. That's fine.'

"I start Googling it and I'm like, 'Honey this looks like a bungee jump,' and he's like, 'No, no, no it's canyon swing!' I'm looking and I'm seeing these death-defying videos and people posting things like, 'DONT DO IT!' It's a bungee jump and if my boyfriend calls it a swing one more time, I swear I'm going to kill him.

"It's a bungee jump. But here's the problem. I'm with his family! I felt like I was on The Bachelor! I had to be like, 'Are you ready to take this [step]? Can you jump off with him? This is the next step in your relationship.' I'm like, 'Am I gonna get the rose out of this?'"