Before moving on to the next round, ET's Kevin Frazier spoke with Williams on Tuesday night following his performance, where he shared why he chose Wonder's classic song.
"It’s just about the direction the world is going. Sad. It’s something worth singing about though, you know," Williams expressed, adding, "Stevie Wonder is my king and when it comes to music, that's my king. That's what kept me alive most of the time in prison. Listening to him all day, every day."
Williams was able to Zoom with Wonder himself, telling ET, he was in "tears." "It was like tears through the whole Zoom. It really was," he confessed. "I let him know he was my king of music. When it comes to king of soul, you are my king of soul Stevie."
He added that he asked Wonder if he could cover his song, "and he just laughed and said, 'Go for it man!'"
Williams' appearance on the NBC reality competition series came just over a year after he was exonerated and freed from prison after serving over 36 years for a crime he didn't commit. Now he's inspiring people with his perseverance and dedication.
As for how his life has changed since competing on AGT, Williams noted, "Everything has changed for me since that and it’s all good."
"I didn't even know I was talking to him at the moment," Williams revealed. "I'm thinking I was talking to Howie and when he got off the phone, my little cousin, she's telling me what the surprise was about, and I was like, 'You got to be kidding! I was just talking to Elton John?' I'm telling him how much of a fan I am of Elton John -- and didn't even know I was talking to him."
While the two will have to reconnect and perform together amid the coronavirus pandemic, Williams is staying connected with other friends.
"Oh yeah, all the time," Williams replied when asked if he kept in touch with the folks in jail. "I just have guys that I'm really helping with their issues…They're just as innocent as I am, or was, and I reach back to those guys. We correspond all the time. We're really trying to get a program going in prison to help innocent guys be free."
"That means everything to me. To know that I was able to help people that lived in the same conditions that I lived, it just means everything to me to be able to reach out for help and then achieve it," Williams noted. "Simon is the best thing that could've ever happened to me and the Innocent Project."
America's Got Talent airs Tuesdays and Wednesdays at 8 p.m. ET/PT on NBC. For more on William's watch below.