Remarkable scan shows baby Leo smiling even before he was born. Happiest baby ever

At just five months old, baby Leo Hargreaves has already won a host of adoring admirers for his cheeky grin.

But he was actually smiling long before he entered the world, as this remarkable image shows,

The scan, taken at 31 weeks into his mother's pregnancy, revealed he had a huge grin on his face.

His mother Amy Cregg, 24, said: 'My partner Leighton and I were absolutely shocked - even the people who did my scan were amazed.

'But that was just the beginning. After he was born, he was always smiling - even in his sleep.'

Now nearly five months old, Leo has been dubbed the happiest baby in Britain. 

The image is a 4D scan - increasingly popular with expectant parents to get a glimpse of how their child will look. 

Rather then the grainy ‘flat’ images produced by the 2D scanners usually used by the NHS, a 4D machine stitches together pictures taken from a variety of angles to create clear three-dimensional images.

These are then recorded on video – the fourth dimension.

Ms Clegg, from Accrington, Lancashire, said she has already had modelling companies approach her trying to capture Leo’s smile.

The rehabilitation support worker said: 'I’ve been walking in the park and had people come up to me and say "What a gorgeous baby". 

'I’d be interested in him doing modelling but only when he’s older.' 

A spokesman for the company that performed the scan, at Babybond Ultrasound Direct in Burnley, said: 'Our sonographer who scanned Amy and her gorgeous baby was overwhelmed at her smiley baby throughout the entire scan. 

Attracting attention: Leo's parents, Amy Cregg and Leighton Hargreaves, say they have already had modelling companies approach them about Leo’s smile

'I think we can safely say that he is the smiliest baby we’ve ever seen.

4D scans are a highly developed form of traditional ultrasound where very high frequency sound waves are used to produce images of what is inside the body.

As with older forms of ultra-sound, sound waves a emitted from a transducer, or probe, which is placed on the mother's abdomen and then moved to 'look at' areas in the uterus. 

These sound waves bounce back off the foetus, helping to create a 'picture' of the child on a screen.

4D scans use the same frequency of sound waves as in a normal ultrasound. 

But the sound waves are directed from many more angles, producing a 'real-time' video of the foetus as it moves and allowing scientists to say the images are in four dimensions.