An elderly dog meeting her new “little brother” for the first time used just enough energy to play the new pup’s game without tiring herself out.

The old dog, who suffers from tumours around her ribs and is also very deaf, has gone viral on Reddit thanks to the adorable footage.

In the clip, the playful little pup scampers around like a maniac trying to get the bigger dog to join in a companionable game of “chase me.”

For a while, the older pooch looks rather uninterested. But as the running continues, she decides to join in and slowly starts chasing after the pup.

The little pup had a very high-energy approach

The video has been upvoted thousands of times on Reddit after it was shared yesterday (December 25).

Older dogs can often be given a new lease of life by introducing a new pup into the pack. As one commenter on the original Reddit thread commented: “What happened was amazing. My oldest dog came to life. She established herself as ‘mom.’ "

They continued: “She ended up living 20 more months. Her vet clapped every time we came in afterwards as he was as thrilled as I that the pup was indeed the best medicine.”

Most commenters were touched by the two dogs’ bonding, with one saying "I've got something in my eye. I'm not crying. You're crying."

While the older dog used its experience to conserve its energy

Uploader Winfield Bhat angrily dismissed the criticism that his dog was “probably suffering from cardiovascular disease,” pointing out that the dog’s tumours just made it look fat.

Backing him up, another commenter wrote “Love it. I hate the kill joy armchair vets"

It comes after an adorable old dog was filmed “showing off” to his cleaner by playing with his toys.