As an American tradition spanning 77 years, it is certainly a good excuse to be patriotic.
So Katy Perry showed her love for her country when she sported an unusual American flag dress to perform at an event kicking off Fleet Week in New York last night.
The satin frock looked like an asymmetric mini dress on first glance but was revealed in all its glory when the 27-year-old stuck her left arm out on the red carpet.
The dress then transformed into the Star-Spangled Banner – and if that wasn’t patriotic enough, the singer also gave a sweet salute.
Realising her dress was making a fashion statement, Katy kept the rest of her outfit simple.
She sported a pair of black platform pumps and tied her long violet locks into a high ponytail.
The star performed a special show on the Brooklyn waterfront for a group of US sailors, even singing into a microphone decorated with American flag diamantes.
Katy belted out her hit track Part of Me, sticking to the military theme of the occasion with her backing dancers sporting soldier style outfits.
One lucky navy member even got the chance to take to the stage with the pop princess, who slipped on the mystery man’s sailor hat while wrapping an arm around him.
Fleet Week takes place every year and sees military ships dock in various American cities across seven days so that the crews can see the sights.
And Katy was clearly delighted to be asked to be part of such a patriotic celebration.
She posted on her Twitter last night: ‘Sea men dock their vessels in the great city of NYC to experience the land from whence they came. I’m about to give them a show!’