"I grew up as a simple Catholic kid from a government family in Hull, Quebec, so you can imagine how much of a privilege and honour it was for me to have known this one-off, broke-the-mould woman as a great friend," Aykroyd begins his piece published on Empire Monday.
The former Ghostbusters star explains how he met Fisher on Saturday Night Live and how their relationship turned romantic during filming of The Blues Brothers.
"I gave Carrie a sapphire ring and subsequently in the romance she gave me a Donald Roller Wilson oil painting of a monkey in a blue dress next to a tiny floating pencil, which I kept for years until it began to frighten my children," Aykroyd writes before sharing some classic one-liners from the outspoken star.
"One of the most brilliant and hilarious minds of our eon, Carrie would say things like: 'I love tiny babies. When they cry they turn red and look like screaming tomatoes.' OR "This romance is finished the second you let out even a threep. I'll be sick for a year.'"
Other notable tidbits from the letter include Aykroyd sharing how Fisher's mother Debbie Reynolds would cook for them and how her brother Todd Fisher would take the comedian out on joyrides on a motorcycle.
Aykroyd ended the letter by explaining how his romance with the Star Wars star ended. "Carrie wasn't shallow, we had a great time. She was also in love with Paul Simon. She married him but I hope she kept my ring,"
Fisher will still be seen in upcoming Star Wars sequel The Last Jedi. Lucasfilm and Disney have also announced that there are "no plans to digitally recreate" Fisher for future Star Wars movies.