Hearn, best known for his work playing keyboards for the Barenaked Ladies, joined Reed's band in 2009. Hearn grew up listening to Reed as a young man near Hamilton, Ont.
"It's strange, I'm grieving both my musical hero and a dear, dear friend at the same time," Hearn said Monday in an interview with Matt Galloway on CBC Radio's Metro Morning.
Reed is being remembered as an immensely influential songwriter for his work in The Velvet Underground and later as a solo artist.
As his career progressed, Hearn eventually found himself auditioning for his childhood hero in 1999.
"[Reed] set up his guitar and he started playing and he said 'OK Kevin, if I play this and asked you to play a melody on top, what would you do?' He did that over and over, different ideas coming at me from different angles."
Hearn was able to impress Reed with his own musical chops and extensive knowledge of songs known to only the most hardcore Lou Reed fans.
At one point Reed asked Hearn: "How do you know that? Nobody's heard that song except you, me and seven seagulls."
From that meeting both a friendship and a musical collaboration flourished.
When Hearn was diagnosed with leukemia, Reed sent him a get-well note.
It said: "Hello Kevin, this is Lou. I hear you're not doing well. I hope you get better soon and get back to your music."
Galloway asked Hearn about Reed's reputation as a difficult interview subject and a man with little patience for journalists.
Hearn recalled one instance when he pointed out to Reed a series of positive reviews of his band's recent shows.
"He said 'Kevin, I don't want to hear about the reviews. Take a word from the wise, I don't think you should read them either. He said 'One day they'll be really nice to you and the next day they'll say something so personal and hurtful you won't understand it.'"
A last goodbye
Hearn said he visited Reed in hospital in Cleveland last week.
"I kind of knew it might be goodbye and I actually got to say goodbye, which I'm really grateful for."
Hearn said Reed will be remembered as a musician who cleared the way for others.
"He broke the ground for what we know as alternative music," said Hearn. "He really introduced singing honestly about darker subject matter and introducing a literary sensibility into rock music and real poetry in music."
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