"Arnold Schwarzenegger ... You know what? He died ... I was there," Trump told the press, according to Yahoo News, reported by People.
"The president was talking about Apprentice ratings when he quipped that Schwarzenegger 'died.' Real life and death stuff," Walker wrote in a tweet.
Schwarzenegger spotted the tweet and responded like a boss, tweeting, "I'm still here. Want to compare tax returns, @realDonaldTrump ?"
This is the latest in an ongoing feud between the two celebrities-turned-politicians about the NBC reality series.
The former Governor of California, Schwarzenegger, said in 2017 that he would step down as host because of the "baggage" brought with Trump's association.
"I loved every second of working with NBC and Mark Burnett. 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," he told Variety at that time.
His statement came after an interview with Empire magazine, as cited by People, in which he said he will not return to the show even if asked to. He also stated that viewers were "boycotting" the show because Trump still had an executive producer credit.
"I learned a lot, I had a great time, it was a really great opportunity. But under the circumstances, I don't want to do it again," he told the outlet back then.
"With Trump being involved in the show people have a bad taste and don't want to participate as a spectator or as a sponsor or in any other way support the show. It's a very divisive period now and I think this show got caught up in all that division," he said.
While the actor blamed the declining ratings on Trump's involvement in the show, Trump claimed that Schwarzenegger was simply bad at the job of hosting.
"Yes, Arnold Schwarzenegger did a really bad job as Governor of California and even worse on the Apprentice...but at least he tried hard!" he tweeted in 2017.
After which, the actor brought up the fact that Trump has never released his tax returns to the public. The US President's tax returns continue to be the talk of the town since he failed to release them on the 2016 campaign trail.