No, Def Leppard.
That's the band's actual spelling. They were emulating phonetic spelling of Led Zeppelin. The reason Led Zeppelin spelled their name that way was because originally they were going to spell it "Lead Zeppelin"(after the idea that they'd go over like a lead balloon), but their management were afraid that people would mispronounce the word "Lead" as "
leed" so they shortened it to "Led."