Young thief returns stolen guinea pig

A seven-year-old has been reunited with her Christmas guinea pig after a guilty young boy returned it. 

The father of seven-year-old Bianca Anderson told 9NEWS he saw a young boy playing with "Bobby" in front of their Collier Crescent home, in Brunswick, on Saturday.

"He knocked on my door on one occasion, and asked if he could play with the guinea pig...I wasn't too concerned," Dean Anderson told 9NEWS this morning.

Returning back inside to his daughter, Mr Anderson didn't see the boy leave his front yard with the pet guinea pig presumably in hand.

But this afternoon, the young thief returned 'Big Bobby' to Bianca, who says it was lovely to "get him back".

The young man thought the guinea pig was so cute he decided to take him home himself.