Kaley Cuoco wept with emotion as she unveiled her star on the Hollywood Walk of Fame.

The 28-year-old Big Bang Theory actress, who plays ditzy neighbour Penny in the E4 comedy hit about a group of geeky scientists, said she had cried before the ceremony even started.

Kaley Cuoco and husband Ryan Sweeting attend the ceremony

Kaley Cuoco and husband Ryan Sweeting attend the ceremony (AP)

Flanked by her co-stars Jim Parsons, Johnny Galecki, Simon Helberg and Kunal Nayyar, Kaley revealed the 2,532nd star on Hollywood Boulevard.

Speaking after the ceremony, she said: “That was crazy, I was very overwhelmed. I’ve been overwhelmed for the past month, I’ve been really nervous about this.

“Especially to be recognised for something that I love so much is extremely touching. To have my family here and my friends, it’s a very special day.

“I never thought this would happen, I have known two people to be inducted and I thought that was the coolest thing, so for them to bring my name into this, and this is here forever and I can prove to my kids I am cool, I cannot wait.”

Kaley posed for selfies with her co-stars and her husband, Bahamian tennis pro Ryan Sweeting, before the ceremony and, in an emotional speech before the unveiling, she said the show had changed her life.

“I already started crying in the car on the way over here so I got that out of the way.

Kaley Cuoco with her co-stars

Kaley Cuoco with her co-stars (AP)

“When they called me a year ago I thought they made a mistake so I am going to talk really fast to make sure it’s really in there.

“I have been doing this for my whole life and it’s heart-warming to me to be recognised for something that is so a part of me. It’s like my arm, it has always been me. There’s nothing else I’ve ever known and nothing that I have loved so much. So to be recognised for something that is me and what I was born with means the world. I am completely honoured and completely blessed and extremely touched.”