Kaley Cuoco had to rehome her beloved dog when she began having "mega fights" with her fiance's pooch.

The 38-year-old actress has paid a tribute to her former pet Shirley - who has died of cancer - and explained fans hadn't seen her canine companion on her social media channels for some time before her passing because she had to live elsewhere due to tensions with Tom Pelphrey's pet.

She said in an Instagram Reel: "Most of you know I had [Shirley] for many, many, many years. All of a sudden, you kind of stopped seeing her, and I started to get a lot of questions as to where she was, because it's very unlike me to just stop posting about a dog that I've had since she was six weeks old.

"Long story short, she's a very special dog to me, as you all know.

"And when the love of my life came into my life, Tom, who is also a mega dog lover, and he moved across the country with his beautiful German Shepherd, Blue, a couple years ago, unfortunately, Blue and Shirley started getting into some mega fights."

The 'Big Bang Theory' actress - who has 19-month-old daughter Matilda with Tom - praised Shirley as "such a people dog" but she grew concerned as she was "determined to kill" Blue and began scrapping with other dogs, except for her pet Norman, who she had grown up with and was "the mob boss".

Kaley ultimately concluded Shirley could no longer live with her and her many other dogs because of "how she was behaving".

She added: "I loved her so much, but I was really scared. I didn't want something really bad to happen or possibly a person accidentally be there and get hurt."

Shirley went to live with the 'Flight Attendant' star's pet handler Tony and his wife Angie.

Kaley added: "They have loved her so so much, and it was an excruciating decision."

Sadly, Shirley recently passed away.

Her former owner cried as she said: "She got a very aggressive bone cancer that came on very quickly.

"She was almost 14 years old, which is an unbelievable life for a dog. And I just wanted to share her story and what we had to do."