By Deena Zaru, CNN

(CNN) -- Hip-hop artists -- from Diddy to Killer Mike -- rallied behind Colin Kaepernick and other athletes this week after President Donald Trump urged owners of the NFL to fire the "sons of bitches" who protest the National Anthem on the field.

"THE LINE HAS BEEN CROSSED!!!! Time to show them #blackexcellence LETS GO!" Diddy tweeted, along with a widely shared meme that compares Trump's description of African-American players as "sons of bitches" and the President's previous suggestion that there were some "very fine people" on both sides of a white supremacist rally in Charlottesville, Virginia.

Diddy, who used to have a friendly relationship with Trump in the 1990s, urged fans to take action in a minute-long video posted to Twitter.

Atlanta rapper T.I., who recently spoke with CNN's #GetPolitical about police brutality, shared the same Charlotesville meme, tweeting "Who da F--- made Pennywise the President???" in a reference to the horror reboot "It," along with a clown emoji representing its antagonist.

Trump's comments targeting African-American players who participated in National Anthem protests came while the President addressed supporters at a rally in Alabama Friday night.

The President encouraged fans to "leave the stadium" when players take a knee and urged NFL owners to respond to anthem protests by saying, "Get that son of a bitch off the field right now, he's fired. He's fired!"

Atlanta rapper Killer Mike, who backed Vermont Sen. Bernie Sanders in the 2016 election, compared Trump's comments to Supreme Court Justice Ruth Bader Ginsburg's criticism of the anthem protest last year. Ginsburg apologized to Kaepernick last October for calling the protest "dumb and disrespectful."

"Same thinking, "Boy How dare U", no matter if it's from Ruth or Donald," the Run the Jewels rapper wrote on Instagram. "It's all "Obey And Honor the State Over Humans". Don't be disgusted by one and not the other tho u Son's of bitches."

Atlanta rapper David Banner defended those who take a knee, tweeting, "America doesn't give a f--- about black people so why should we pledge to a bloody ass flag. You have never made amends for slavery."

Hip-hop mogul Russell Simmons, who wrote a letter to his "old friend" Trump during the 2016 campaign urging him to "stop fueling fires of hate," urged the NFL to stand up to Trump.

"The @NFL must protect its heroes and not be intimidated by Trump's attacks," he tweeted. "They must be loud, unapologetic and forceful in their response."

These attacks against the President are part of a larger trend in hip-hop, which turned on Trump in 2016 after nearly three decades of idolizing his wealth and power in hundreds of lyrics.

Hip-hop artists have been been raising awareness about police brutality and racial inequality in both music and activism since the 1980s. And Kaepernick, who became one of the most controversial figures in sports when he took a knee last year to protest police brutality, has since been mentioned in tens of lyrics advocating for social justice, including songs by J. Cole, Kendrick Lamar, Rapsody, Eminem and Lupe Fiasco in "Kneelin' on Needles."

Kaepernick is now a free agent and has not been signed by any NFL team. This has caused some to speculate whether the league is shunning him for his protests on the field.

Last week Jay-Z dedicated "The Story of O.J." -- a song that the rapper said is about how "we as a culture" can empower each other economically -- to Kaepernick, the late Dick Gregory and "anyone that was held back and you overcame."

And J. Cole, who is currently one of hip-hop's most socially conscious rappers, performed in a Kaepernick jersey and helped promote the former NFL players' "Know Your Rights" campaign.

Cardi B, who is most known for her single "Bodak Yellow," threatened to boycott the NFL if they don't hire Kaepernick and gave him a shout-out while speaking on stage at the MTV Video Music Awards last month.

"Thanks so much @iamcardib I appreciate you supporting the movement and @yourrightscamp," Kaepernick tweeted.