Simon Tofield, who is behind the popular YouTube animation series , has previously donated proceeds from 'Simon's Cat' t-shirt sales to the charity.
Now he has created a two-minute clip, 'Fed Up' starring Simon's Sister's Dog, for the charity that highlights how feeding dogs scraps from the dinner table can lead to overweight pets.
It has notched up 16,245 views on Tofield's YouTube page since being posted yesterday.
The charity is encouraging people to embed the clip on their websites.
The RSPCA has an online community, Pets Get Slim, helping people to help their pets lose weight. It claims pet obesity is one of the biggest issues affecting pets' health and one in three of the UK's cats and dogs are now overweight.