Alexander Wang was a ''fanatic'' when he first met Madonna.

The 31-year-old designer was chosen by the songstress, 57, to design her costumes for her current Rebel Heart Tour, but he has admitted he acted like a crazy fan and even asked for a photograph when he first met her a few years ago.

Speaking to WWD.com, he said: ''I met her a couple of years ago. I think I was at the Met [Ball Gala] and I was very fanatic and asked to take a picture with her, and it was a moment, and I remembered it forever, and I was like, OK, I guess that was my Madonna moment.

''She came to our Met after party last year. We got to talk a little bit more and then from there, she asked me to be in the video and then from there, she was like, 'I have the tour coming out. Would you be open to working on something?'''

The fashionista, who has been in the industry 10 years, was thrilled he was chosen to design Madonna's costumes but was taken aback by her knowledge of fit, style and material.

He said: ''She's very educated in terms of fit, in terms of material, what works for her body. The most important thing for her is the performance comes first and foremost, so she has to be able to dance and move and feel comfortable in it.

''So she knows exactly what she wants. But, yes, it was a huge privilege for us, and an honour.''