The LED thing

I recognized a Cat Stevens song on the radio the other day. So I was confused when my new fangeled LED thing on the radio said the words "Yasuf, formerly Cat Stevens". That is a mouthful for an LED display, & it didn't really help when I yelled at the radio "What is going on????" At first I thought this Yasuf person was just covering a Cat Stevens song, but it sounded so much like him. That's because it was. Apparently, I'm out of the loop & Cat Stevens changed his name in 1977. I wasn't even born yet, so why do I know him as Cat Stevens? I'm really out of the loop.