Meghan Markle makes surprise America's Got Talent cameo to cheer on wrongfully convicted contestant Archie Williams

Meghan Markle appeared on the finale of America's Got Talent with a surprise message of good luck for a contestant who previously spent decades in prison for a wrongful conviction. 

The Duchess of Sussex stunned 59-year-old singer Archie Williams via a pre-recorded video, saying she and Harry had been "cheering him on every week". 

Joking that it wasn't just because the couple were partial to the name Archie, which they called their now one-year-old son, Markle said they had been "moved" by the man's story. 

According to the Daily Mail, Williams was wrongfully convicted of raping and stabbing a woman in 1982. He was selected from a photographic lineup, despite fingerprints from the crime reportedly not matching his own. He was incarcerated for nearly 37 years before being proven innocent by the FBI's fingerprint database last year. 

"So a very special message to you that I will probably be saying all of my life, but this night, it is specifically for you," Markle addressed Williams. 

"Archie, we are proud of you and we are rooting for you, and we can't wait to see what you do. We're in your corner. Have a good night!" she said. 

Williams appeared emotional as he waved back at the screen after the former Suits actress signed off. 

Williams did not go on to win America's Got Talent 2020, but according to the New York Times, he could be entitled to up to US$250,000 compensation for his wrongful incarceration - around US$7,000 for every year he spent behind bars.