Sen. Marco RubioMarco Antonio RubioCOVID-19 makes Trump's work with black Americans that much harder China reports no new COVID-19 cases for first time since outbreak Trump, GOP go all-in on anti-China strategy MORE (R-Fla.), who has yet to endorse de facto GOP presidential nominee Donald TrumpDonald John TrumpBiden slams Trump in new ad: 'The death toll is still rising.' 'The president is playing golf' Brazil surpasses Russia with second-highest coronavirus case count in the world Trump slams Sessions: 'You had no courage & ruined many lives' MORE, said Thursday he would be willing to speak for the businessman at the party's national convention in July. 

ADVERTISEMENT

"If Donald Trump asked you to speak on his behalf, you would do so?" CNN's Jake Tapper asked Rubio.

"Certainly, yeah. I want to be helpful," responded Rubio, who was one of Trump's most vocal critics during the Republican primary.

"I don't want to be harmful because I don't want Hillary ClintonHillary Diane Rodham ClintonTrump escalates fight against mail-in voting Sunday shows preview: States begin to reopen even as some areas in US see case counts increase The Electoral College is not democratic — nor should it be MORE to be president. My policy differences with Donald Trump — I've spent a lot of months talking about them, so I think they're understood." 

Rubio, who suspended his campaign in March after losing badly to Trump in his home state, has previously declined to explicitly support or endorse Trump, instead saying he will "support the nominee." 

But Rubio has changed his tune, saying he would be "honored" to help Trump, who reached the 1,237 delegates needed to secure the Republican nomination Thursday, according to The Associated Press.

"I most certainly would be honored to be considered for that," Rubio told Tapper.

When asked earlier this month whether he would speak on behalf of Trump's nomination, Rubio demurred

"Donald Trump would be best served by having people out there working for him that agree with his policies and are enthusiastic about this campaign and enthusiastically supporting the things he has stood for," Rubio told the "Today" show.

Rubio on Thursday did not address rumored “pressure” from the GOP to change his mind and run for reelection to the Senate this November, but he left the door open for seeking political office in the future.

"I can tell you I enjoy public service. If there's an opportunity to serve again in a way that I feel passionate about, I'll most certainly think I would explore it," Rubio said. "But I don't know where I'm going to be in two years. I don't know what my life will look like then."