Taylor Swift can't stay silent about politics any longer.

The 28-year-old superstar took to Instagram on Sunday night to weigh in on Tennessee’s closely contested U.S. Senate race, endorsing Democratic former Gov. Phil Bredesen as she offered a harsh rebuke of U.S. Rep. Marsha Blackburn, the Republican nominee.

Her endorsement of Bredesen marks the first time Swift has spoken publicly about politics.

"As much as I have in the past and would like to continue voting for women in office, I cannot support Marsha Blackburn," Swift wrote, elaborating that "her voting record in Congress appalls and terrifies me."

'These are not MY Tennessee values'

Swift specifically noted Blackburn's vote against reauthorizing the Violence Against Women Act, versions of which Blackburn has opposed in recent years. She also condemned Blackburn's stance against marriage equality

"These are not MY Tennessee values," Swift wrote.

Swift pledged her support for both Bredesen and U.S. Rep. Jim Cooper, D-Nashville, but didn't mention former Nashville Mayor Karl Dean, the Democratic gubernatorial nominee running against Republican businessman Bill Lee.

Blackburn's campaign didn't immediately respond to a request for comment.

More:Shake it off: Taylor Swift's political endorsement draws praise, backlash

In a statement in response to Swift's endorsement, Bredesen's campaign emphasized his efforts to appeal to voters across the party lines.

"It’s clear that Governor Bredesen’s message of working together to get things done is resonating with Democrats, Independents, and Republicans throughout the state," the statement said.

Polls show tight race to replace Corker

Blackburn and Bredesen are campaigning to succeed the retiring U.S. Sen. Bob Corker in the Nov. 6 general election. Early voting begins Oct. 17. Polls have shown a close contest between Blackburn and Bredesen, although recent Fox News and CBS polls show Blackburn with an increasing lead.

The singer's announcement came the day after she finished the North American leg of her Reputation Stadium Tour.

It also came two days after Bredesen's announcement that he supported the confirmation of Brett Kavanaugh to the U.S. Supreme Court, news that has drawn criticism on social media from some Democrats across the state and nation.

In her Instagram post, Swift said she has been "reluctant to publicly voice my political opinions, but due to several events in my life and in the world in the past two years, I feel very differently about that now."

"I always have and always will cast my vote based on which candidate will protect and fight for the human rights I believe we all deserve in this country," she wrote. "I believe in the fight for LGBTQ rights, and that any form of discrimination based on sexual orientation or gender is WRONG. I believe that the systemic racism we still see in this country towards people of color is terrifying, sickening and prevalent."

The post prompted a swift response from the Nashville chapter of the Human Rights Campaign.

“We are so grateful to have a friend in Taylor Swift. Speaking out on women’s rights and LGBTQ rights from her position brings them into the forefront," the group said in a written statement late Sunday. "We are so proud of her for voicing her Tennessee values.”