Lexington Mayor Jim Gray filed Tuesday morning to seek the U.S. Senate seat held by Republican Rand Paul.

Gray entered the Democratic primary on the last day candidates could file as a Democrat or Republican, according to the Secretary of State’s Office. As of Monday evening, no high-profile candidates had filed to challenge Paul.

Gray was elected Lexington’s mayor in 2010, making history as the city’s first openly gay chief executive. Before that, he served four years on the Lexington City Council.

Paul filed for a second term in the Senate last year. He is simultaneously campaigning for president and Senate.

In a video announcing his candidacy, Gray hit on what will likely be his campaign’s theme: restoration of the “American Dream.”

“Instead of building things up like my family taught me, Washington is busy tearing things down,” Gray said. “I want to change that.”

Doug Stafford, senior adviser for Paul’s campaign, said in a statement that the candidate “hopes voters will remember his tireless work to balance the budget, his fight against President Obama’s War on Coal, his fight against Obamacare, and that Senator Paul has returned to the taxpayer over $2 million from his office budget.”

The National Republican Senatorial Committee was quick to respond to Gray’s entry into the race.

“Since their most recent wipeout in November, Democrats have been desperate to find a warm body to run for Kentucky’s U.S. Senate seat,” the NRSC said in a statement.

This story will be updated.

Photo courtesy Jim Gray/Lexington Mayor’s Office