Former Republican presidential nominee will call Donald Trump "a phony" and "a fraud" when he gives a speech on the 2016 presidential race Thursday.

"Here's what I know," Romney will say. "Donald Trump is a phony, a fraud. His promises are as worthless as a degree from Trump University. He's playing the American public for suckers: He gets a free ride to the White House and all we get is a lousy hat."

Romney, the GOP's nominee in 2012, will say that though he understands "the anger Americans feel today," past presidents "have channeled that anger, and forged it into resolve, into endurance and high purpose and into the will to defeat the enemies of freedom. Our anger was transformed into energy directed for good."

"Donald Trump says he admires Vladimir Putin, while has called George W Bush a liar. That is a twisted example of evil trumping good," Romney will say.

Romney, who has stepped up his criticism of the billionaire businessman in recent days, will speak at 11:30 a.m. Eastern time Thursday at the University of Utah's Hinckley Institute of Politics Forum.

"His domestic policies would lead to recession. His foreign policies would make America and the world less safe. He has neither the temperament nor the judgement to be president," Romney is expected to say. "And his personal qualities would mean that America would cease to be a shining city on a hill."

Romney will also warn that a Trump nomination "enables" Hillary Clinton's victory.

"Trump relishes any poll that reflects what he thinks of himself," he'll say. "But polls are also saying that he will lose to Hillary Clinton."

He said only Ted Cruz, Marco Rubio and John Kasich have "serious policy proposals" and should be considered as Republican nominees.

Romney — who many hoped would jump into the 2016 race — is not expected to make any other announcements in his speech today.

Trump was already coming out against Romney's remarks Thursday morning, and asked, "Why did Mitt Romney BEG me for my endorsement four years ago?"