Today the U.S. Postal Service unveiled a new stamp honoring writer Maya Angelou. The only problem? The quote featured on the stamp isn't hers.

The stamp has an image of Angelou, along with the quote: "A bird doesn't sing because it has an answer, it sings because it has a song." The quote actually comes from a 1967 book of poetry by author Joan Walsh Anglund called A Cup in the Sun.

Anglund's original quote used "he" instead of "it" to refer to the bird. But for what it's worth, Anglund isn't upset about the misattribution, telling the Washington Post that she wasn't aware that the stamp was being made but that she hopes it's successful.

Earlier this morning First Lady Michelle Obama and Oprah Winfrey were on hand in Washington to help unveil the stamp. The President even misattributed the quote to Angelou in a 2013 speech -- an error that nobody seems to have caught at the time.

New stamp features fake quote from Maya Angelou

"Had we known about this issue beforehand, we would have used one of [Angelou's] many other works," a spokesperson for the Postal Service told the Washington Post. "The sentence held great meaning for her and she is publicly identified with its popularity."

So who's to blame? The U.S. Postal Service, of course. But probably the internet as well. A quick search through Google Books reveals that the quote wasn't attributed to Angelou in the 20th century. Which means this attribution really only took off in the past decade or so on the internet, where attribution of quotes to the wrong person tends to spread like wildfire.

As Albert Einstein once said, "Never trust a quote you found on the internet."