A new limited edition “Forever” stamp honoring the late poet and author Maya Angelou was released by the U.S. Postal Service on Tuesday, and features a quote that may not have actually originated from the iconic civil rights champion. While Angelou is responsible for the fame of the quote “A bird doesn’t sing because it has an answer, it sings because it has a song,” relatively unknown children’s book author Joan Walsh Anglund is claiming that it originated in her 1967 book of poems “A Cup of Sun.”

The U.S. Postal Service officially dedicated the new “Forever” stamp at a Washington ceremony on Tuesday. The stamp features Ross Rossin’ 2013 oil painting of Angelou, which is currently displayed in the Smithsonian’s National Portrait Gallery collection, and the quote which Anglund recently told The Washington Post first appeared in her book of poems.

“It’s an interesting connection, and interesting it would happen and already be printed and on her stamp,” said Anglund, who didn’t know in advance the stamp would include her quote. “I love her and all she’s done.”

Angelou used the quote several times throughout her career, causing several people to mistakenly attribute it to her for years; President Obama even gave her credit for the quote while presenting the National Medal of the Arts and Humanities last year. However, USPS spokesman David Partenheimer claims that the Postal Service knew that the quote didn’t belong to Angelou, but included it regardless since she referenced it frequently.

“Maya Angelou cited this sentence frequently in media interviews and other forums and it provides a connection to her first memoir `I Know Why the Caged Bird Sings,'” said Partenheimer. “The sentence was chosen to accompany her image on the stamp to reflect her passion for the written and spoken word. The sentence held great meaning for her and she is publicly identified with its popularity.”