Celebrities at 2019 U.S. Open: Katie Couric, Regina King, Alec Baldwin and more

It's just the beginning of the 2019 U.S. Open and tons of famous faces have already been spotted in the crowd cheering on their favorite tennis pros.

Gigi Hadid came out to the Billie Jean King Tennis Center to support her good friend Serena Williams. The supermodel stunned in a Canadian tuxedo and suede Louboutin booties with Missoma jewelry. Hilaria and Alec Baldwin attended the tennis tournament on opening day, as did Spike Lee and legendary soul singer Gladys Knight.

Oscar-winning actress, Regina King, visited the Tennis Channel suit looking sporty in a Ellesse sweatsuit while Queen Latifah watched Novak Djokovic rally it out during the men's singles second round.

From Katie Couric to "Stranger Things" star Natalia Dyer, check out all of celebrities who got their game faces on at the U.S. Open this year.