When Donny Osmond surprises Jennifer Garner on her birthday, she freaks out.

Jennifer Garner received a very unique gift from her childhood idol, Donny Osmond, for her upcoming 50th birthday.

On Friday, the “Alias” star, who turns 50 on April 17, posted a video of Osmond, 64, singing to her on her big day on Instagram. Then, much to Garner’s surprise, Osmond appeared behind her to finish the song.

The two hugged, and the singer of “Puppy Love” gave her a cake with the words “13 Going on 50,” a reference to her favourite film, “13 Going on 30.” They then sang a duet before Garner covered her face with a napkin, evidently overwhelmed.

“My first (pre)birthday surprise was a doozy— the one and only, legend in his own time, object of my childhood adoration and devotion— the one and only, legend in his own time, object of my childhood adoration and devotion— @donnyosmond showed up to knock my purple socks off,” she wrote alongside the video, referring to Osmond’s trademark purple socks.

“He took an hour and a half of his day to sit with me, sing my favorites, and to give me a master class on how to be a class act. Thank you, Donny. 💜 Hi, @marieosmond. ☺️,” she wrote before adding that she “hopes to meet” Osmond’s wife Debbie.

Diane Keaton, Holly Robinson Peete, and Sara Foster, among Garner’s celebrity friends, expressed their joy, while Gwyneth Paltrow remarked, “This is unreal.”

In May 2019, Katie Couric posted a flashback video of Cher singing with The Osmonds in gaudy jumpsuits, revealing Garner’s childhood obsession on Osmond.

“My number one biggest crush of all time @donnyosmond,” Garner commented, along with a kissing face emoji.

Osmond responded by joking, “Miraculous that those jumpsuits didn’t scare you away.”

Garner went insane after the singer shared a photo of their encounter on his Instagram Story.

“1st Grade Jennifer is freaking out right now,” she wrote after she reposted to her own.