Jennifer Garner received quite a special gift ahead of turning the big 5-0.

The actress, who turns 50 on Sunday, April 17, was overcome with emotion when her idol Donny Osmond surprised her with a video singing to her for her birthday.

In a clip shared to her Instagram, Garner is sitting at a restaurant as she watches a video of Osmond singing to her on her phone. The moment becomes even more surreal when Osmond walks up right behind her chair and belts the rest of the lyrics in real-life.

Garner immediately covers her face with her hands as she's in awe. She then gets up, turns around and gives Osmond a hug.

DONNY OSMOND ON SURVIVING CHILD STARDOM AFTER BEING CALLED A ‘HAS-BEEN’: ‘WASN’T GOING TO DO IT WITH SCANDALS’

Osmond, 64, didn't come empty-handed. He handed the actress a cake that said "13 going on 50" on it, in honor of one of the star's most memorable movies, "13 Going on 30."

Jennifer Garner received quite the surprise from Donny Osmond ahead of her 50th birthday. 

Jennifer Garner received quite the surprise from Donny Osmond ahead of her 50th birthday.  (Getty Images)

The actress, with a big smile on her face, nervously shared that she was "so hot" she had to take her sweater off. Osmond then sits down and the two sing together at the table.

"My first (pre)birthday surprise was a doozy— 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," Garner wrote in a caption of the post she shared on social media.

"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. I hope to meet you someday, Debbie," she added.

CLICK HERE TO SIGN UP FOR OUR ENTERTAINMENT NEWSLETTER

Garner revealed earlier this year that her birthday, which falls on Easter, will be special because she'll be joined by family.

Jennifer Garner 13 Going on 30

Donny Osmond gifted Jennifer Garner a cake inspired by her movie, "13 Going on 30." (SGranitz/WireImage)

"My family has tickets to come out. My parents and my sisters, nieces and nephews. I don't know what we'll do, but I can't wait," Garner told People magazine last month.

CLICK HERE TO GET THE FOX NEWS APP

Jennifer Garner turns 50 on Sunday.

Jennifer Garner turns 50 on Sunday. (Photo by Amy Sussman/Getty Images for Baby2Baby)

Garner shares three kids with ex-husband Ben Affleck: Violet, 16, Seraphina, 13, and Sam, 10. Affleck made headlines last week when Jennifer Lopez revealed he proposed for a second time.