Los Angeles: Veteran action star Arnold Schwarzenegger is in stable condition after undergoing heart surgery.

TMZ first reported that the former governor of California underwent emergency open heart surgery, but his spokesperson, Daniel Ketchell released a statement on Twitter that the procedure was planned.

“Yesterday, Governor Schwarzenegger underwent a planned procedure at Cedars-Sinai to replace a pulmonic valve that was originally replaced due to a congenital heart defect in 1997.... Governor Schwarzenegger’s pulmonic valve was successfully replaced and he is currently recovering from the surgery and is in stable condition. We want to thank the entire medical team for their tireless efforts," Ketchell said in the statement.

Ketchell added that an open heart surgery team was on hand as part of standard procedure, but was not needed.

Schwarzenegger, who served as governor of California from 2003-2011, is set to return to the Terminator franchise for the sixth film in the series, which is scheduled for release by Paramount on 26 July 2019.