Beyonce and Jay Z's daughter thinks she is their ''friend''.

The couple spend as much time as possible with three-year-old Blue Ivy so the little girl doesn't see their bond as one of parent and child.

Beyonce's mother, Tina Knowles, told E! News: ''She's with her parents seven days a week and, you know, that's such a blessing that she can be with her parents all the time.

''Sometimes she thinks she's a friend more than the kid.''

Last month, Blue Ivy made a special handwritten card bearing the phrase ''#1 Mom'' for the 'Crazy in Love' hitmaker's 34th birthday.

Proud mum Beyonce shared a picture of the card on her Instagram account and thanked fans for their own well wishes.

She said: ''Thank you from the bottom of my heart for all my birthday wishes.''

Blue and her father also surprised the star by naming their favourite songs that remind them of the singer in a post on her official website.

Blue picked the song 'Part of Your World' from the Disney classic 'The Little Mermaid', commenting: ''Mommy you sung this to me all the time. Happy birthday, Mommy!''

Jay, meanwhile, picked Coldplay's smash 'Yellow'.

He said: ''This song reminds me of you and I on vacation. 'Look at the stars, look how they shine for you.' So many legendary nights. It represents vulnerability; it's us in our own world, away from work and totally lost in love. 'For you, I'll bleed myself dry.' ''