If anyone ever tells you friends don't come in all different shapes and sizes, they're lying. 

When Digby the Chihuahua, who is five weeks old and weighs half a kilo (one pound), met Nero the Neapolitan mastiff, who weighs 60 kilos (132 pounds), at Southridge RSPCA Animal Center at South Mimms, it was friends at first sniff. 

Digby may be the size of Nero's nose, but he has no problem keeping up with his new giant friend.

Animal shelter workers said in a news release that the two pups have been inseparable since RSPCA Animal Collection officer Natalie Ditchfield brought the Chihuahua to the shelter. 

Ditchfield found Digby cowered in a blanket shivering and dehydrating between two garbage bins in North London on Jan. 26. 

The scared, abandoned puppy soon perked up once he was rescued and introduced to Nero. 

"It was as if the little fellow took on Nero as his personal minder!" Center Manager Anna White said in the news release. "Poor Digby had to be rescued once by the RSPCA and it seems like he is taking precautions to make sure nothing can happen to him again."

If you looked at Digby, you would never guess that just a few days ago he was abandoned in the cold. Now, the brave pup's story is warming the hearts of people all over the internet. 

"It is so lovely to see he is safe and happy. When I first came across Digby he was frozen and shaking and had just been left to die. He's really tiny - small enough to fit in the palm of my hand," Ditchfield said.

RSPCA is still investigating how Digby got into those bins in North London.