In an open letter posted to the website Globalgrind, Simmons, the chairman of The Foundation for Ethnic Understanding, urges Trump to "stop the bulls---" and "stop fueling fires of hate."
"Don't feed into the rhetoric created by small-minded people. You're smarter and certainly more loving then you let on," Simmons writes, adding, "I know the cheap seats are easy to play to, but you can get them just by being the man I have known for nearly 30 years."
In his letter, Simmons reflects on his 30-year plus friendship with Trump, who endorsed his books, attended his shows, flew him on his private jet and invited Simmons' family to stay at his Florida home.
"So, it kinda pains me to know that my public statements about your candidacy have strained or ruined our friendship," Simmons continues. "However, the fact is, what's at stake is bigger than us."
Trump, who has long been a celebrity in his own right prior to his presidential run, has been known for his relationship with hip hop moguls like Simmons and has been name-dropped in hip hop lyrics for decades.
In a recent interview with CNNPolitics, hip hop legend KRS-One said that while none of the presidential candidates "are cool with hip hop," Trump "was a friend to hip hop in his early days" because In the 90s you could always find Trump around hip hop artists like P. Diddy.
"He was closer to the urban community, urban America," KRS said. "When we say, look, Donald Trump was a friend to hip hop back in the day, so was Bill Clinton. It doesn't mean that because he was a friend to hip hop back in the day, that the same Bill Clinton wasn't at the lead of this mass incarceration of African-Americans today," he added.
As for Trump and Simmons' friendship? Simmons says while he wishes Trump "good luck on (his) path toward the White House," he will be "campaigning rigorously against (him)."