The 71-year-old commander-in-chief left the NBC series in 2014, before Schwarzenegger swooped in as his replacement a year later.
However, despite still serving as executive producer of the hit reality show, Donald Trump continually put down his successor.
Following Schwarzenegger’s announcement that he’s quit Celebrity Apprentice USA, Trump hurled wild accusations against the beloved actor.
“Arnold Schwarzenegger isn’t voluntarily leaving the Apprentice,” Trump tweeted, “He was fired by his bad (pathetic) ratings, not by me. Sad end to great show.”
Schwarzenegger hit back: “You should think about hiring a new joke writer and a fact checker.”
Trump’s outburst comes as the film star – turned politician – turned Donald Trump stand-in – told CNN that he wouldn’t be returning to the reality series.
“I loved every second of working with NBC and Mark Burnett,” he said. “Everyone – from the celebrities to the crew to the marketing department – was a straight 10, and I would absolutely work with all of them again on a show that doesn’t have this baggage.”
NBC is yet to comment on the 69-year-old’s departure; nor have they confirmed if the hit US series will be returning at all.
Trump previously claimed viewing figures crashed under Schwarzenegger during last month’s National Prayer Breakfast, asking the crowd to “pray for Arnold”.
Though, Schwarzenegger responded in the most Arnie way possible, raging: “Hey Donald, I have a great idea. Why don’t we switch jobs?
“You take over TV because you’re such an expert on ratings and I take over your job and then people can finally sleep comfortably again.”
Celebrity Apprentice wrapped up last month with American Ninja Warrior host Matt Iseman being crowned the winner.
Previous title holders include Piers Morgan, Joan Rivers and Bret Michaels.