The 'Celebration' singer – who has daughter Lourdes, 12, son Rocco, nine, and adopted children, David and Mercy, both four –is incredibly busy raising her family and touring, but hasn't ruled out the possibility of extending her brood further.

Asked if she will be a mother again, she replied: 'Who knows? I have my hands full right now! I have no idea! That's all I'm going to say. But we never say never.'

Although she wants more children, Madonna – who is rumoured to be planning to marry boyfriend Jesus Luz – won't be extending her family in the near future as she has several charity projects and movie ventures filling her spare time.

She explained: 'I have several projects going. I have another script that I've written, and I want to direct another film. Hopefully, I'll be doing that next year. I also have many projects going on in Africa right now that I want to bring to fruition, like building a girls school and working on two new documentaries.'

If Madonna does decide to have another child, she will get plenty of support from her eldest daughter.

She told website Popeater: 'Lourdes is super-sister. She's amazing with the little ones. She has the typical relationship with her brother, Rocco. They're like, 'I love you/I hate you' every five minutes. But with the two little ones, she's great. She's amazing. Very protective.'

Lourdes appears in the video for 'Celebration' but her mother doesn't believe she will follow in her footsteps as she prefers to act, an ambition the singer has vowed to support.

She said: 'I don't think she wants to be a singer. I think she wants to be an actress. I'm fine with it, as long as she finishes school, and takes it seriously. She also plays piano, and she's really into clothes and fashion and style.'