This is the skin-crawling moment a man went to the toilet and found a huge monitor lizard happily swimming in the water tank.

Attasit Charoensuk, 32, heard a splashing noise when he walked into the bathroom at his home in Thonburi, Thailand, on Sunday afternoon.

He was stunned to see the four foot long reptile swimming in the water tank which is used for storing water for having a shower.

The monitor lizard happily swims around a green pipe, left, before sinking to the bottom of the water tank, right, in Thonburi, Thailand

Video recorded in the bathroom shows the beast in the top right hand corner of the tank next to a green pipe.

As Mr Charoensuk talks to the camera the lizard moves around the tank, showing off its long tail.

It eventually drops to the bottom left corner before the video jumps to a clip after it has been taken out of the tank and is crawling on the floor next to the toilet.

Mr Charoensuk said he grabbed the beast by the tail and yanked it from the water before dropping the reptile onto the tiles and watching it scurry away.

The four foot long reptile stretches out, left, as it swims before the video changes to a clip showing the lizard, right, on the bathroom floor

The sales worker is heard in the video saying: 'You little blighter, what are you doing in my bath. Look at you, swimming away happily.

'Are you trying to hide from me? Come on, you can't hide from me.''

Speaking afterwards, Attasit said: 'It looks like we have a new member of the family. I hope my wife doesn't get jealous.

'I was scared when I saw the lizard and after I pulled it out I ran away.'