Steven Tyler and Joe Perry shared the lead.
Run DMC sang Walk This Way with Aerosmith.
Aerosmith
Steven Tyler, Aerosmith's frontman
aerosmith
aerosmith
Steven Tyler
Lenny Kravitz
Steven Tyler, their lead singer, wrote it.
I don't know which one you are talking about. It seems that there are many songs called Walk Away. here are a few of the writers. Kelly Clarkson Franz Ferdinand Ben Harper James Gang Hope it helps.
I don't think anyone sung it on season eight, but someone named Michael Johns sung it on season seven.
Aerosmith
Aerosmith is a band