A supporter wears a t-shirt with faces of the former president during a rally held by former U.S. President Donald Trump in Washington Township, Michigan, U.S. April 2, 2022.
A supporter wears a t-shirt with faces of the former president during a rally held by former U.S. President Donald Trump in Washington Township, Michigan, U.S. April 2, 2022. Reuters / EMILY ELCONIN

Former U.S. President Donald Trump on Saturday said he is endorsing celebrity surgeon Dr. Mehmet Oz, who is running as a Republican in a closely watched U.S. Senate contest in Pennsylvania.

"Dr. Oz is smart, tough, and will never let you down, therefore, he has my Complete and Total Endorsement," Trump said in a statement.

The Senate race in Pennsylvania could determine control of the Senate and the fate of Democratic President Joe Biden's agenda. A crowded field of candidates are vying to replace the retiring Republican Senator Pat Toomey.

Trump "knows how critical it is to change the kinds of people we send to Washington. I'm ready to fight," Oz said in a statement. "I thank him for that, and I am proud to receive his endorsement."

The top Republicans in the race are Oz and David McCormick, a former hedge fund CEO. Recent polls had Oz and McCormick neck and neck in the Republican primary contest to be held on May 17.

On the Democratic side, Pennsylvania's progressive lieutenant governor, John Fetterman, is locked in a race against Congressman Conor Lamb, a moderate representing the northwestern suburbs of Pittsburgh.

Toomey was one of seven Republican senators who voted to convict Trump in February 2021 following Trump's impeachment on a charge that he incited last year's attack on the Capitol by Trump supporters. The Senate vote of 57-43 fell short of the two-thirds majority needed to convict Trump.

Oz, known for the syndicated "The Dr. Oz Show," brings substantial name recognition to the wide-open Nov. 8, 2022, contest.

Oz rose to fame shocking audiences with show-and-tell displays of decaying lungs and rotting livers, telling viewers they should take care of themselves.

His public image took a blow in 2014, however, when he told lawmakers probing bogus diet product ads that some of the products promoted on his show lacked "scientific muster." Senators at the hearing focused on green coffee bean extract, a dietary supplement Oz touted in 2012 as a "miracle."

Trump in September 2021 endorsed Sean Parnell for the open Pennsylvania seat Oz is vying for. But Parnell suspended his campaign in November 2021 after his estranged wife alleged physical abuse and he lost a battle over the custody of his three children.