Former California governor and film star Arnold Schwarzenegger, Commando had open-heart surgery in California on Thursday.

His representative, Daniel Ketchell, said that the surgery was successful and that 70-year-old Schwarzenegger is in stable condition at Cedars-Sinai Hospital in Los Angeles after they had replace an aging pulmonic valve.

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

Schwarzenegger, who had a congenital heart defect, had undergone pulmonic valve replacement in 1997.

That valve was "never meant to be permanent," Ketchell said, and had reached the end of its life expectancy, which was approximately 10 to 15 years. The valve used in the new surgery was a less-invasive catheter valve replacement, he said.

The pulmonic valve sends blood from the heart's lower right chamber to the artery that delivers blood to the lungs. If it doesn't function properly, it can cause fatigue and shortness of breath during exertion, as well as fainting spells.

The Austrian-American actor is best known for his roles in "Conan the Barbarian," "True Lies" and "The Terminator" series. Later in life, he moved to politics and served two terms as governor of California, from 2003 to 2011.

CNN