Washington DC - Ultimate Fighting Championship (UFC) chief Dana White turned down President Donald Trump's – apparently jovial – offer of a job as press secretary in a surprise appearance at the White House on Monday.

Trump stunned the world by saying on social media on Saturday that he had asked White to take on the high-profile post – but a day later the 80-year-old president said he was "only kidding."

The 57-year-old cage fighting boss visited the White House on Monday, and Trump brought him out for a chaotic news conference in the James Brady Briefing Room.

"So let me ask you the big question. Would you like to be press secretary of the United States of America? Or do you just want to stay with this ridiculous UFC? Huh?" Trump said.

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"Thank you for the offer, sir – for the offer, I have no, no – I do not want to be in politics," White replied.

Trump smiled and headed out of the room, saying: "I am devastated to hear this. Goodbye, everybody."

The press secretary's post has been been vacant since Katie Zacharia left on October 16 after less than a week in the post. Her combative predecessor Karoline Leavitt left in August after a year and a half in the job.

Trump's announcement that he had offered the high-profile job to "violent Fighter and Warrior" White had sparked speculation that he was ready for an aggressive stance after the Republican Party's stunning midterm election defeat.

White is a long-time friend of the president and helped host a massive UFC match on the White House lawn earlier this year.

But there was also some skepticism about the president's announcement, and Trump said Sunday night that he had been joking.

Leading out White to the podium on Monday, Trump said he had been "having a little fun."

"He's a great guy," Trump told the room full of reporters. "The only problem is he'll talk for a little while, and then he's going to beat the hell out of you."

Standing at the lectern and wearing a black T-shirt and jacket, White looked like he might be more comfortable in the octagon – the ring used for UFC fights.

"I've always wanted to do this. Who has the first question?" he joked – before quickly adding: "I have zero political aspirations."

White added that "the last 24 hours of my life has been insane" since Trump made the announcement.

Asked by a journalist to confirm he had said no to the job, White added: "I don't tell the president 'no' to anything... I didn't want to be disrespectful and say anything until he said something first."