According to the advocacy group Death Penalty Focus, Snoop will attend a rally Saturday outside San Quentin Prison. The Long Beach, CA rapper originally requested a visit with Williams but his application for entry was denied.

“We were unable to provide him with a security clearance because of his arrest history,” said San Quentin spokesman Vernell Crittendon.

Before launching his music career, Snoop (born Calvin Broadus) spent time in prison on drug-related offenses. In 1993, he faced charges in connection with a drive-by shooting, but was later cleared. Snoop also once associated with the Crips.

Williams was sentenced to death in 1981 for killing four people in two robberies. He is scheduled to be executed on December 13.

During his years on death row at San Quentin, Williams has garnered international praise for penning books aimed at keeping children out of gangs, among other peace-preaching efforts.

Further attention was brought to Williams’ case by an award-winning television biopic, Redemption: The Stan ‘Tookie’ Williams Story. The film starred Jamie Foxx as Williams. The oscar-winning actor is also among the supporters seeking clemency for Williams.

More than a dozen other rallies supporting Williams are scheduled around the state in the next few weeks; including a Danny Glover-hosted documentary film screening about Williams in San Francisco and a round-the-clock vigil outside the prison from December 4 until the execution date, when people from across the country are expected to demonstrate.

Saturday’s rally is scheduled for 10 a.m. pst outside San Quentin’s gate, according to Death Penalty Focus.