LOS ANGELES (AP) — Kim Kardashian West isn’t the only celebrity speaking out for prison reform. It’s a topic that was also very important to slain rapper Nipsey Hussle, and to Common, Kevin Hart and a host of others who consider the criminal justice system often unfair and dehumanizing.

Hussle served time before he was shot to death on March 31 and was raising awareness for changes. Last October, he headlined a free #TimeDone campaign concert to bring awareness to the 70 million Americans living with a past conviction.

In February, while attending the Grammy Awards, Hussle explained why the topic of prison reform was among his priorities.

“I grew up in South Central Los Angeles. You know we come from gang culture so we dealt with the system a lot,” he told The Associated Press. “We saw firsthand over-sentencing, unfair probation, the policies and stuff, so to see people putting energy into reforming that and just making it a little closer to what’s fair, you know what I mean? I think that it’s an important subject. It’s an important movement that we should all support.”

Hussle was on the advisory board of WordsUncaged, a nonprofit where prisoners serving life sentences learn to reclaim their voices and reflect upon the harm they have caused through narrative therapy and creative writing workshops.

Songwriter and record executive DJ Mustard, who is a Grammy winner and has collaborated with Hussle, has a cousin, Theodore, who is currently incarcerated. Mustard said prison reform is “super important” to him because often, people are “accused of something they didn’t even do.”

“They take the time for it not knowing, not having any lawyers, not even being in the right state of mind to even fight the case or even have enough money to get a lawyer to fight the case,” he said.

His cousin was sentenced to 80 years to life as a teenager.

“At that time, we didn’t have money to go for a good lawyer and now we’re fighting and fighting and fighting to get him out. That’s a lot of people’s cases throughout the world,” Mustard said.

Common, a Grammy, Oscar and Emmy winner, was touched in particular by the cause through his work on the 2014 film “Selma,” the story of the 1965 voting rights marches in Alabama. The “Glory” rapper has performed at numerous concerts inside California prisons and is a frequent visitor to the men of one in Los Angeles County where all are serving life sentences.

“I think one of the things that I’ve experienced from meeting men and women who were incarcerated was that they wanted to feel humanized. They wanted people to know that they were human beings,” Common said.

“The places that I’ve been, I’ve met some of the best human beings I’ve ever met in my life in prison that were doing life without parole that had actually committed violent crimes and had committed murders, but then were able to acknowledge that and try to move past it and do the work.”

Hart also has spoken out about the need for criminal justice reform because of what has happened with his friend, rapper Meek Mill.

Mill has become a symbol for reform after a judge in Pennsylvania sentenced him to two to four years in prison for minor violations of his probation in a decade-old gun and drug possession case. He spent months in prison before a court ordered him released.

“He had to go back, and they put them in for this crazy amount of time. So, seeing that, going and visiting firsthand, we realize that there is a large portion of people that have been convicted that are set up to get convicted again regardless of their good behavior,” Hart said.

According to the Prison Policy Initiative , a nonprofit that documents the effects of mass incarceration, the criminal justice system holds almost 2.3 million people in state and federal prisons, juvenile correctional facilities and local jails. More than 540,000 of those haven’t been convicted.

The NAACP said that between 1980 and 2015, the number of people incarcerated in the United States increased from roughly 500,000 to over 2.3 million. African Americans and Hispanics comprised 56 percent in 2015.

“We just have to, in society,” Common said, “not just look out for the people that can do for us but look out for those who are overlooked.”