(CNN) New York City Mayor Bill de Blasio endorsed Bernie Sanders in the 2020 presidential race, the Vermont senator's campaign said Friday.

De Blasio, who is set to campaign with Sanders in Nevada ahead of the caucuses there, became the first former 2020 contender to back Sanders. He'll join Sanders at a rally Sunday in Carson City.

"Mayor Bill de Blasio knows that the only way we can defeat Donald Trump is by uniting people from all backgrounds around an agenda that speaks to the needs of working families," Sanders said in a statement to CNN. "Jane and I grew up in Brooklyn and we are so proud to have the support of a New York City mayor fighting every day to improve the lives of New Yorkers. Bill is a leading example of what bringing the Democratic Party together around so-called 'radical ideas' like universal pre-K, paid family and sick leave, and defending immigrant neighbors can do for our country."

The relationship between Sanders and de Blasio traces back further than the current election cycle. Sanders spoke at the mayor's second inauguration , on New Year's Day in 2018. Though his own presidential bid fizzled, de Blasio has a strong base of support among African American voters in New York and remains one of the few high-profile progressive Democrats to have won high office powered by a multiracial coalition.

"I am standing with Bernie because he stands with working families, and always has," de Blasio said in a statement on Friday night. "New Yorkers know all too well the damage caused by Donald Trump's xenophobia, bigotry and recklessness, and Bernie is the candidate to take him on and take him down. I have called for a bold, progressive agenda, and that's exactly what Senator Sanders has championed for decades. I am proud to endorse a true progressive leader who will fight for working New Yorkers and families across the country."