This the adorable moment a 200lb dog welcomed home his new sibling - a tiny kitten.

Otto Von Barksmark, an English Mastiff, welcomed the tiny Fritz Carlton, a 16-week-old kitten, at home 10 weeks ago.

A video shows Otto shifting nervously and staring at his new sibling with a strange mixture of excitement and fear.

Owner Trent Koen, 27, said: "He had no idea what to do with himself."

"He didn't even want to make eye contact."

Trent, a clerk at a law firm in Dallas, Texas, USA, adopted Fritz from a rescue center.

Fritz was chosen specifically for Otto as Trent knew that any new pets had to get along with him.

Trent said: "It was actually love at first sight. Fritz is very dog-like for a cat. He'll come over and sit on my lap or go over and cuddle Otto."

Otto and Fritz have been under the same roof for 10 weeks now but the pup is still a bit nervous

Trent said: "Fritz will try to cuddle with Otto and he'll lie with him for a while and then get up to look at me like: 'Am I OK?'"

"He's not just scared of Fritz. Late at night, after Otto has climbed into my bed, Fritz will often be there with him."