Kiwi couple's 'grumpy' cat goes viral for falling in love with his dog brother

A Samoyed dog and grumpy cat have gone viral online after falling in love with each other.

Christchurch-based photographer Rinsa Li, 29, loves taking photos of her two pets, a six-year-old Samoyed dog, Casper, and two-year-old grumpy cat, Romeo.

Her husband, 27-year-old Wei Cheng, says he "can't imagine a life without them".

The unlikely pair spend their time road-tripping through scenic destinations like Lake Tekapo, West Coast and Queenstown. Their travels are photographed on Instagram, where they've racked up more than 38,000 followers.

Grumpy Romeo and happy-go-lucky Casper love cuddling on the couch together and playfighting - but Romeo's favourite activity is when his dog brother licks his flat cat face.

"Romeo has a flat face, so that's why he always looks grumpy, but I think he's actually pretty happy," Wei told Newshub.

Rinsa has always wanted a cat, but was worried about how Casper would react.

"When my best friend got a cat, I took Casper to meet them and it turns out Casper was curious, but was very gentle and sweet," Rinsa said.

"After this, all my doubt disappeared, and I decided to start looking for my dream cat; and I found Romeo."

The pair were separated for the first week as Rinsa swapped their blankets to get them used to each other's scents.

"Casper was sweet; he would go up to Romeo and smell him. If Romeo got scared, Casper would gently move away and sit at a distance to make sure Romeo felt safe."

Romeo was nervous at first, but the pair soon became inseparable. The now "king of the house" is always secretly following Casper around, seeking his attention.

"I think sometimes he thinks he's a dog," Wei said.

"He's not a shy cat; he likes to come out to people, greet people, kind of like a dog."

Casper sometimes gets jealous of Romeo, but still looks after him like an older brother. 

"I actually think Casper likes Romeo more than me and Rinsa," Wei said.

"[Romeo] kind of grew up with Casper, when Romeo was younger he always slept on Casper's dog bed as well, it was super, super cute."

When the couple goes on holiday, Casper stays at a friend's house while Romeo remains home. When Casper returns, Romeo won't leave Casper's side, like he missed his big brother.

"It kind of seems like Romeo's thinking. 'Where have you been?'" Wei said.

Wei, who works from home, says having them next to him is "very reassuring", as he can feel their unconditional love.

"I never really bonded with a cat, and then after getting Romeo it's just like, wow.

"When they look at you, and they meow at you, you're like 'okay I'll pick you up, I will serve you, I will serve you to the best of my ability'," he joked.

"They're basically our kids. When people ask if we have kids we say 'we have two fluffy kids', that's enough for us.

"Our dream is to give them the best life we can."

The couple never expected the following they've gained on Instagram, but are pleased their content is making people smile and laugh.

They also share their pets' adventures on Facebook, and recently started a YouTube channel.