Fans have been lined up for hours outside the Greater Grace Temple awaiting the chance to attend the service, which will feature performances by Stevie Wonder, Ariana Grande, Jennifer Hudson and speeches by former President Bill Clinton, the Rev. Jesse Jackson and Smokey Robinson.
Franklin's body was brought to the church in a white hearse that carried the body of her father, minister C.L. Franklin, in 1991 and civil rights leader Rosa Parks in 2005; and like them, she will be buried in Detroit's Woodlawn Cemetery.
One of Franklin's most iconic performances was at President Obama's 2009 inauguration, where she sang "My Country, 'Tis of Thee" in an over-the-top grey hat with a giant, rhinestone-studded bow.
On a more personal note at the funeral, Franklin's granddaughter, Victorie Franklin, said she knew Franklin more as a grandparent than a musician.
The former president also asked the audience to forgive him, saying he was happy that Franklin's casket was still open when he arrived because he just had to see what she was wearing. Pink Cadillacs filled the street outside the church, a reference to a Franklin hit from the 1980s, "Freeway of Love".
Floral arrangements from singers such as Barbra Streisand and Tony Bennett and from the family of the late Otis Redding, whose "Respect" Franklin transformed and made her signature song, were set up in a hallway outside the sanctuary.
The Mayor of Detroit also announced Friday his intentions to rename the city's largest outdoor music venue the Aretha Franklin Park. "This is not a concert, this is not a show, this is not an awards production". "Most of these people have affected the world in some way, but Aretha is in her own very special category".
Friday's service will touch on Franklin's significance to her friends, family and fans, organizers told CNN.
"I love her and I respect who she was and who she is and all of those kinds of things", Knight added.
The church's choir sang Franklin's "Say a Little Prayer" and her version of "Bridge Over Troubled Water" as mourners arrived.
"I didn't know, especially this soon, that I would have to be say goodbye to you", he said.