Cheryl Cole's happiest moment was witnessing the birth of her nephew.The Girls Aloud singer was her sister Gillian's birthing partner and she says it was an incredible honour to see the tot coming into the world. The 29-year-old beauty said: ''When I was 16 years old my sister announced that she was pregnant and that she would absolutely love for me to be her partner at the birth so as you can imagine, at 16, watching your first nephew and first grandchild of the whole family being born is an insane memory, is the best feeling you could ever have. I experienced emotions I didn't even know I had and I felt incredibly blessed to be there at his birth.'' Cheryl also says the moment it was announced she had won her place in Girls Aloud on 2002 talent show 'Popstars: The Rivals' is another event she will never forget. In an exclusive video for jewellery company Pandora, the 'Call My Name' singer - who is joined in the band by Kimberley Walsh, Sarah Harding, Nicola Roberts and Nadine Coyle - said: ''When we were first announced as being in the group that will always be one of the memories that sticks in my mind more than anything because of the feelings I had attached to that memory. ''I can only describe is at as like euphoria, excitement and happiness. That is one of the best feelings I've ever had and I will never forget.''