Former GOP presidential nominee Mitt Romney will announce Thursday that he's running for the Utah Senate seat held by retiring Orrin Hatch, three people with direct knowledge of the plan confirmed Wednesday.

The former Republican presidential candidate will release an online video Thursday announcing he's running for the seat. His first public appearance as a Senate candidate will be Friday night at a county Republican party dinner in Provo.

Those with knowledge of the plans spoke on the condition of anonymity because they weren't authorized to speak publicly.

Romney, a former Massachusetts governor and one of the most famous Mormons, is expected to easily win the Senate seat in Utah, which is heavily Mormon.

The 70-year-old Republican moved to Utah after losing the 2012 presidential election and is very popular in the state. He helped turn around the scandal-plagued 2002 Winter Olympics and has earned broad respect in the state.

In addition to his instant name recognition, Romney has a deep network of fundraisers and his own personal wealth to help carry him.

President-elect Donald Trump and Mitt Romney shake FILE - President-elect Donald Trump and Mitt Romney shake hands as Romney leaves Trump National Golf Club Bedminster in Bedminster, N.J., Nov. 19, 2016. FILE - President-elect Donald Trump and Mitt Romney shake hands as Romney leaves Trump National Golf Club Bedminster in Bedminster, N.J., Nov. 19, 2016.

?Vocal Trump critic

If he becomes Utah's next senator, some supporters hope the vocal critic of President Donald Trump could serve as a political and moral counterweight to a president they see as divisive, erratic and undignified.

He does not address Trump directly in the announcement video, however. In fact, he plans to maintain a hyper-local focus on Utah voters during the campaign.

During the 2016 presidential election, Romney gave a scathing speech in which he called Trump "a phony" who is "playing the American public for suckers" and a man who was unfit to be president.

He softened his stance after Trump won the presidency and put himself forward as a candidate for secretary of state. But he resumed his criticism last year, calling out the president for blaming "both sides" following a deadly white supremacist rally in Charlottesville, Virginia.

Trump, in turn, had criticized Romney for his failed presidential bids in 2008 and 2012, saying he "choked like a dog."

Any efforts by Trump to block Romney are unlikely to resonate in Utah, where the president received a lukewarm reception from Mormons who were repelled by his brash demeanor and comments about women and minorities.

Romney isn't expected to face any serious challenges for the seat. Even Utah's conservatives who see him as too moderate and establishment for their liking admit they respect him and are unlikely to block him.

Romney was treated last year for prostate cancer, which an aide said was removed surgically and found not to have spread.

Senate Health, Education, Labor and Pensions Commi FILE - Senate Health, Education, Labor and Pensions Committee member Sen. Orrin Hatch, center, is seen on Capitol Hill in Washington, Jan. 31, 2017. FILE - Senate Health, Education, Labor and Pensions Committee member Sen. Orrin Hatch, center, is seen on Capitol Hill in Washington, Jan. 31, 2017.

?Hatch's plans

Hatch plans to retire after 2018, following more than four decades in the Senate. One of the longest-serving senators in U.S. history, Hatch began floating Romney's name last year as his potential successor.

When Hatch won re-election in 2012, he pledged that his seventh term would be his last. He flirted with breaking that promise, suggesting he might run again in 2018 with the encouragement of Trump, who has sought to block Romney.

In the end, Hatch decided to stick with his promise, saying, "Every good fighter knows when to hang up the gloves."