The 'You Make Me Feel Like Dancing' hitmaker was due to spend time with the late King of Rock and Roll at his Graceland mansion in Memphis, Tennessee - along with his then-fiancée Ginger Aldean - the day before the 'Hound Dog' hitmaker tragically passed away aged just 42, in August 1977.
Elvis got in touch with Leo through his security guy, Michael, after he helped nurse the 70-year-old star back to good health after a nasty fall.
And when the 'Suspicious Minds' hitmaker rang inviting him over, Leo believed it was a ''hoax'' at first.
Speaking exclusively to BANG Showbiz, Leo said: ''We talked on the phone.
''I'd fallen off stage and a guy who was working with him in Memphis took me under his wing and helped me get back to fitness because I was in a bad way, especially when I got to do the gig in Memphis, they had to cancel it.
''This guy took me to over to Alabama, to his health club.
''I asked him why he was down here and he said he worked exclusively for one guy in Memphis.
''He said, 'I can't really tell you who it is. Well, maybe I can ... but not now.'
''The next day he handed the phone to me, and said it's my boss.
''I was talking on the phone and he answered, 'It's Elvis Aaron Presley.
'''I want you to come and see me in Graceland tomorrow.'
''I went, 'What!? Excuse me?'
''I thought it was a hoax imitating him, you know?''
The Grammy-winner was gobsmacked when the music legend told him he was a fan and wanted to make music with him.
He continued: ''He said, 'No, I really am Elvis and I love your songs, in fact, 'You Make Me Feel Like Dancing', I want you to give me some of your energy man, let's make some music together.'''
Leo woke up the next day to the news that shocked the world, that Elvis had died of a
He recalled: ''We were going over there. We were planning it the next morning, and I turned on the radio and I heard a broadcast saying that he had been taken into Memphis Baptist Hospital, and was dead on arrival.
''Michael [his security] rushes into my room and says, 'I've got to go, did you hear the news?'
''That is the last I saw of Michael and I never got to see Elvis.''
Asked what music he thinks the pair would have made together, he said: ''Can you imagine if we got together?
''I daren't imagine what kind of music we would've made.
''But I knew we would have been singing together and doing something amazing.''
Leo Sayer is playing Rewind North in Capesthorne Hall, Cheshire on 4 August along with The Jacksons, Marc Almond, Billy Ocean, Tiffany and many more. Tickets are now available through rewindfestival.com
It's time for a riot grrrl revolution.
How are the world's biggest superstars changing?
Who inspired Royse?
Graham J tells all about his experience with the Jazz Journal.
An interview with Nick Wilson.