Song Hye Kyo, who volunteered to narrate the documentary 'May, the Children,' reportedly choked up at the part of a sick child on the deathbed. 

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A KBS rep stated, "During the recording of the narration which took place the day before the documentary, we had to halt the recording twice. It was during a scene where a child is on the deathbed. Song Hyeo Kyo was so choked up with emotion." 

'May, the Children' is a documentary about Seoul University children's hospital's Kim Min Sun and her 120-day documentation of four terminally ill children who fight death by living their lives to the fullest. The second part of this documentary, titled 'May, the Children 2,' will air this coming May 11 at 10 p.m. (KST).