This is the moment a hero four-year-old boy saves his toddler sister from drowning in a paddling pool.

Shocking CCTV footage shows how the girl – named only as Alice – flips upside down in the water.

Alice – just 17 months old – is seen trying to grab a toy when the floating turtle she is sitting in overturns.

As she struggles under the float, her brother Theo quickly turns her the right way up during the drama at the family home in Sorocaba, Brazil, on 27th November.

The clip was released by the family recently to warn other parents about dangerous inflatable rings.

The pair had been left alone in the pool by their father while he went off to check on a barbecue.

The footage shows him rushing back to the pool as he hears the drama unfolding.

As he holds his daughter in one arm, he hugs his son with the other and gives him a kiss on the cheek for saving his sister’s life.

Mum Karen Larissa Sene, 32, told of the moment she watched the security camera footage of the incident for the first time.

She told local media: “I was moved, in shock at the same time, and very proud of my son.

“I kept this video secret, fearing criticism. After the fright passed, I decided to post it to warn other parents that they can’t trust this water ring.”