Ryan Reynolds, who married Blake Lively in 2012, is still learning new things about his wife.

The actress and proud mother recently debuted a new hair care line called Blake Brown. While taking to Instagram to celebrate Lively and her accomplishment, Reynolds revealed that she had no idea that Brown was actually Blake Lively's official last name.

"I'm insanely proud of this woman. She's been working on @blakebrownbeauty for 7 years," Reynolds wrote on her Instagram Stories, People reported. 'And the results are exactly what you'd expect from a super picky, detail-addicted, uncompromising quality control genius. Also, I just learned that her last name is Brown."

Reynolds is not the only one a little surprised to learn that Lively is not Blake's "real" last name. The actress recently explained the status of her last name to reporters at a New York event celebrating the release of her latest film.

"Brown is my father's name. My father got Lively from my mother. It's a longer, more interesting story," Lively explained at the time, as reported by People. 'But I thought it was really cool. My mom has three kids, and he said, 'I'm not going to take their names, and I'm not going to let them take mine. I'm just going to take their names.' That was before I was born.

Lively explained that his father took the Lively surname and, as a result, "has only ever been called Blake Lively," even though it actually appears on his birth certificate.

"Blake Brown is on my birth certificate and then it appears in legal documents all over the place. Blake Brown is on my birth certificate and then it shows up here and there in legal documents. But it was my most intimate identity because it's kind of my most personal name."

Lively's father is not the only husband or partner who has decided to take his wife's last name; according to one 2023 Pew Research study, only 5% of heterosexual men take their wife's last name upon marriage, and less than 1% of men choose to hyphenate their last names.

Lively said that since people "don't know anything" about her official last name (including her husband, apparently), it was important to her to honor her real last name through her new hair care line, and to speak openly about her father's decision to take her mother's last name She said.

"People don't know anything about that," she explained at the time. 'It was very important to me to put my name on this brand.'