Former US House Speaker John Boehner. Thomson Reuters

Former House Speaker John Boehner held nothing back while discussing the 2016 presidential election at Stanford University on Wednesday.

He even went as far as calling Ted Cruz, the Texas senator vying for the Republican nomination, a "miserable son of a bitch."

"Lucifer in the flesh," the former speaker said, according to The Stanford Daily, a student newspaper.

He continued: "I have Democrat friends and Republican friends. I get along with almost everyone, but I have never worked with a more miserable son of a bitch in my life."

Boehner said he would vote for GOP presidential frontrunner Donald Trump in a general election. He said he had played golf with the Manhattan billionaire, whom Boehner considers a "texting" buddy. Boehner said, however, that he would not vote for Cruz if Cruz became the nominee.

Cruz responded around noon Thursday. He said Boehner's comments, in which he called Cruz "Lucifer in the flesh," showed that the former House speaker had "allowed his inner Trump to come out."

The GOP presidential hopeful, standing alongside his newly announced potential running mate in Carly Fiorina, also said he had no previous working relationship with Boehner.

"Truth of the matter is I don't know the man," Cruz said, adding that he'd be surprised if he's said more than 50 words to him. "I've met the man two or three times."

Oddly enough, Cruz served as Boehner's counsel for a case during the late 1990s.

Boehner has leveled several rounds of blunt criticism at Cruz over the past few years, and the two repeatedly clashed when Boehner led the House Republican caucus. Late last year, Boehner referred to Cruz as a "false prophet" and a "jackass."

Turning his focus over to the Democratic primaries, Boehner reportedly impersonated former Secretary of State Hillary Clinton.

"Oh, I'm a woman, vote for me," he said, according to the publication, before later adding that he had known Clinton for more than two decades and believed her to be both accomplished and smart.

He did speculate, however, that the controversy over Clinton's private email server could become a bigger issue.

"Don't be shocked … if two weeks before the convention, here comes Joe Biden parachuting in and Barack Obama fanning the flames to make it all happen," he said.