When did Elvis start wearing his trademark jumpsuit?

Well he wasn't wearing it when he did his 1968 comeback special, but he was wearing it when he did Aloha From Hawaii in 1973. So it's between those years. If I had to narrow it down even further, I'd say it was 70-71. I think he did "In the ghetto" in 70 and he wore one, but I can't be sure of that. It's been a looooooooong time lol.