A twin leans over and kisses the cheek of her sister in a heart-warming picture that would not be out of place in any family home.
Yet these siblings are a not even born and the astonishing images have been captured on a new 'four-dimensional' ultrasound scan of the womb.
London-based obstetrician Professor Stuart Campbell, who is the pioneer of 4D scans in Britain, performed the scans for a National Geographic documentary.
He says: 'It was fascinating to see the babies in more detail than ever before. I was amazed at the detail in the faces - smiles, blinking - and the interaction between multiple foetuses.'
The scans were used to particular effect when charting the progress of the naturally conceived, identical quadruplets of Julie Carles, 38, whose story was revealed exclusively in the Mail last year.
The scans showed the four fetal bodies developing in minute detail - it is even possible to see their eyelids opening - as well as their developmental patterns as they jostle for space in the womb. See more photos and the complete article in the Daily Mail