The 'Are You Gonna Go My Way' hitmaker has paid tribute to his friend - who he performed with at the 25th Anniversary Rock & Roll Hall of Fame Concert at New York's Madison Square Garden in October 2009 - following her death from pancreatic cancer on Thursday (16.08.18) and opened up about their close bond, as well as the admiration he had for her as a musician and performer.
In an article for Billboard, he wrote: ''I love Aretha. I've loved Aretha since I was a child. Jackson 5 records, Aretha Franklin records, that was my education.
''The Queen of Soul says it all, and it's absolutely true. She's actually in my top three piano players, too, even if she didn't open her mouth.
''I got to sing with her at Madison Square Garden. We did a duet together and got to hang out with her a bit and talk to her on the phone. She'd call me, I'd call her.
''(She's) the greatest, the greatest, the greatest, the greatest. Just a sweet woman and she just felt like somebody in my family, like one of my aunts. She felt really familiar to me.''
And the 54-year-old rocker recalled how the 'Who's Zoomin' Who' singer could always make him laugh.
He continued: ''And she was funny. I remember in rehearsal she would constantly be telling jokes and she'd start telling me stories. She'd always have some incredibly funny punch line or she'd pull a picture out of her purse of something to show you that was so funny. She was always cracking me up.
''Just a beautiful lady. Demands her respect, and rightfully so.''
Another friend of the 'Daydreaming' hitmaker, record executive Clive Davis, has been left ''absolutely devastated'' by her death.
He said in a statement: ''I'm absolutely devastated by Aretha's passing.
''She was truly one of a kind. She was more than the Queen of Soul. She was a national treasure to be cherished by every generation throughout the world.
''Apart from our long professional relationship, Aretha was my friend. Her loss is deeply profound and my heart is full of sadness.''
Her former backing singer, Cissy Houston, said she would ''deeply miss'' her friend.
She said in a statement: ''I have known Aretha for over 50 years, both professionally as her back up singer and then as a friend.
''We have shared heartbreak, loss, as well as exaltation and great laughter and most importantly our mutual love of God. Although my heart is broken, my soul rejoices that I was able to watch God move through Aretha's life''