"It is Britney's actual dress," Lively told PEOPLE at the premiere. "It should be in the Smithsonian or the Met. But it's on me. I feel so lucky!"

Before arriving at the premiere, Blake shared heartfelt words about Britney on her Instagram Stories.

“Today’s mood: The ultimate queen who made us all want to sparkle and write and share our stories,” Blake wrote. “Britney, us millennials all have a story of a moment, or of years that you made us want to shine and inspire awe, with strength, and joy and immensely hard work. Thank you for your example and your contribution to women telling their stories. So excited about your biopic and all you have to come.”

Blake also chose Britney’s song “Everytime” to be featured in It Ends With Us and included the singer in her list of “thank yous” at the end of the credits.

Britney originally wore the dress at a Versace fashion show in October 2002 in Milan, Italy.

Aligning perfectly with her floral-themed wardrobe this summer, inspired by her character Lily Bloom and her floral shop in the movie, the Versace dress features a few embellished flowers at the waist. The multicolored, sequined dress features a one-shoulder halter neckline and a unique cutout across the bodice.

Lively accessorized with rings from Lorraine Schwartz's fine jewelry line, each matching the dress's vibrant pink and pastel blue colors, along with a pair of dangle drop earrings in the same hues. She completed the look with simple iridescent strappy heels.

Her makeup complemented the dress’s colors, with soft pink eyeshadow and matching matte lipstick. She styled her long blonde hair in loose waves cascading down her back.

Britney originally wore the dress at a Versace fashion show in October 2002 in Milan, Italy.

Aligning perfectly with her floral-themed wardrobe this summer, inspired by her character Lily Bloom and her floral shop in the movie, the Versace dress features a few embellished flowers at the waist. The multicolored, sequined dress features a one-shoulder halter neckline and a unique cutout across the bodice.

Lively accessorized with rings from Lorraine Schwartz's fine jewelry line, each matching the dress's vibrant pink and pastel blue colors, along with a pair of dangle drop earrings in the same hues. She completed the look with simple iridescent strappy heels.

Her makeup complemented the dress’s colors, with soft pink eyeshadow and matching matte lipstick. She styled her long blonde hair in loose waves cascading down her back.