Arnold Schwarzenegger Photo: Courtesy

Arnold Schwarzenegger is in "good spirits' following his emergency heart op, with his first words even being "I'm back".

The 70-year-old muscle man was rushed into surgery for an emergency heart operation.

However his spokesperson insisted that he was in a stable condition following the op and even joked around.

Daniel Ketchell tweeted that Schwarzenegger was awake, adding: "His first words were actually 'I’m back', so he is in good spirits."

The actor and former California governor was taken to Cedars-Sinai hospital in LA on Thursday for a catheter valve replacement - but developed complications while he was there.

As a result, doctors took the decision to give him emergency open-heart surgery in an operation that lasted several hours, TMZ reports.

The Terminator star is still recovering in hospital but is said to be in a stable condition.

Schwarzenegger was seen at an NBA game in Los Angeles, USA on February 18 2018 Photo: Courtesy

Arnie has previously experienced heart difficulties in 1997 when he needed an aortic valve replacement.

It comes months after the star schooled Donald Trump in how to condemn Nazis after the white supremacist march in Charlottesville, Virginia last August.

Arnie decided to help his US Apprentice predecessor out by rewriting the president's response to the march, which was widely condemned.

Arnold slammed Trump for failing to condemn 'Nazis'.

Trump drew criticism for claiming there was blame on "both sides" of the clashes, suggesting there were "fine people" among the neo-Nazis and suggesting equivalence with the anti-fascist counter protest.

Arnold hit out at the President and pledged to donate $100,000 (Sh10 million) to anti-hate organisation the Simon Wiesenthal Center.

“There are not two sides to bigotry. There are not two sides to hatred. And if you choose to march with a flag that symbolises the slaughter of millions of people, there are not two sides. The only way to beat the loud, angry voices of hate is to meet them with louder, more reasonable voices.And that includes you, President Trump”