Madonna gave Kim Kardashian her iconic rubber bracelets when she was a little girl and had no idea she had met the reality TV star before until they were reunited at the Met Ball this month.The 'Girl Gone Wild' singer had no idea she first bonded with the 'Keeping Up With The Kardashians' star in the 1980's until they were reunited at the Met Ball in New York earlier this month.The 54-year-old singer told 'Extra': "I met her years and years ago when she was a little girl, believe it or not."She told me she was a huge fan of mine, and it was during the time I was wearing all of the rubber bracelets on my arms."I took off all of the bracelets and gave them to her, and then I completely forgot about it. She reminded me when I saw her the other night. Now she's a pregnant lady!"Meanwhile, Madonna also revealed that she still struggles to balance her career and motherhood but encourages her children to work hard.The singer, who has four children, Lourdes, 16, Rocco, 12, David Banda, eight, and Mercy James, also eight, explained: "I try to find the right balance between being there for them and guiding them, and also being an artist."I'm trying to find enough time in the day to do those jobs well."I try to be very clear with them. This is my persona for work. What we aspire to do is, to work and to be good people. If you don't have those two things, fame is nothing, so I try to drill that into their heads."