Thousands of revelers decked out in the red, white and blue will march down New York City's Fifth Avenue for the annual Puerto Rican parade.

Celebrities and politicians take part in the festive event that features colorful floats, costumes and music.

The parade evolved in the early 1950s as a pan-Latino affair but later became more focused on celebrating Puerto Rican heritage.

An estimated two million people are expected to line the streets to watch.

If attending, be aware that several streets in midtown and the Upper East side will be closed.

The parade got under way at 11 a.m. and will proceed along Fifth Avenue from 44th Street to 79th Street, according to the NYPD, which is warning visitors to expect delays disruptions and increased police presence.

advertisement | advertise on newsday

Street closures went into effect at 9:30 a.m. and pedestrian crossings are at:

• 44th Street between Broadway and Vanderbilt Avenue

• 45th Street between 6th Avenue and Vanderbilt Avenue

• 46th Street between 6th Avenue and Vanderbilt Avenue

• 47th Street between 6th Avenue and Park Avenue

• 48th Street between 6th Avenue and Madison Avenue

• Vanderbilt Avenue between 42nd Street and 47th Street

The public should anticipate some traffic delays and disruptions, as well as increased police presence, including specialized units and other deployments in the vicinity of the parade route and nearby transit hubs.

advertisement | advertise on newsday

An uproar recently erupted among the Puerto Rican community over a logo of their island flag on a commemorative Coors Light beer can created for the parade.

Coors is a parade sponsor.

Organizers denied the image was meant to represent the Puerto Rican flag or the parade's logo.