He says Richard Glossip, convicted of ordering his boss’s murder, is innocent and did not receive a fair trial.
The state of Oklahoma issued a last-minute stay of execution until November 6 over concerns about one of the three drugs to be used in the lethal injection, potassium acetate.
Speaking in Dublin, Branson said he celebrated the postponement with Bono. “We were particularly celebrating last night, a guy called Richard was about to be executed in America, we’re all absolutely convinced he’s innocent, and he got a 40-day reprieve.
“We’ve been campaigning with the government to try and get him reprieved.
“So it gives 40 more days to try and make sure an innocent man doesn’t get executed.”
Owner of the Oklahoma City motel Barry Van Treese, Glossip’s boss, was found beaten to death in 1997.
Glossip was found guilty of recruiting his co-worker Justin Sneed to carry out the killing.
His conviction was based on the evidence of Sneed, who negotiated a life sentence by claiming Glossip masterminded the murder.
For almost two decades, Glossip has proclaimed his innocence while his lawyers have questioned Sneed’s credibility.
Branson took out a full-page advertisement in an Oklahoma newspaper before the planned execution on Wednesday accusing the state of putting to death a man whose guilt has not been proven beyond reasonable doubt.
Pope Francis has also appealed against the execution.
In Dublin to rebrand UPC as Virgin Media, Branson revealed he cried when Germany declared it was opening its doors to migrants.