Cal. Welfare and Institutions Code § 18939.5

Notwithstanding any other provision of law, an individual who naturalizes while receiving benefits under this article, who remains otherwise eligible for benefits under this article, and who applies for federally funded Supplemental Security Income (SSI) and fully cooperates in the application and administrative appeal process of the Social Security Administration, shall continue to receive benefits under this article until the individual receives SSI benefits or has exhausted all appeals for their initial federal SSI application. A recipient shall not be entitled to receive duplicate payments for any month.