Arnold Schwarzenegger stable after open-heart surgery

'Terminator' star Arnold Schwarzenegger, who underwent a heart surgery this week, is now in a stable condition.

His spokesperson, Daniel Ketchell, said on Twitter that on Thursday, the 70-year-old "underwent a planned procedure to replace a pulmonic valve that was originally replaced due to a congenital heart defect in 1997."

"Schwarzenegger is awake and his first words were actually 'I'm back', so he is in good spirits," Ketchell tweeted.

"That 1997 replace valve was never meant to be permanent and has outlived its life expectancy, so he chose to replace it yesterday through a less-invasive catheter valve replacement," he said. "During that procedure, an open-heart surgery team was prepared, as they frequently are in these circumstances, in case the catheter procedure was unable to be performed."

He said Schwarzenegger's pulmonic valve was "successfully replaced" and that the star "is currently recovering from the surgery and is in stable condition," adding, "We want to thank the entire medical team for their tireless efforts."

Schwarzenegger, a former governor of California, is best known for his roles in 'Conan the Barbarian,' 'True Lies' and 'The Terminator' series.