Rachel Bilson & Rami Malek
The O.C. alum attended high school with the Oscar winner, but after sharing a throwback photo from their senior trip to the Big Apple, Rami reached out asking Rachel to take it down.
As she described on Armchair Expert, "...I even wrote to him a really nice message: 'I'm so sorry. Go get the Oscar! You're doing amazing.' And I never hear anything back, which is fine. But I was super bummed because he was always so nice and we were good friends."
Meghan Markle & Katharine McPhee
"Meghan and I did musicals together as kids," Kat wrote on Instagram in 2019. "She grew up to be the Duchess of Sussex and I grew up to star on the West End, so same life if you ask me."
Nowadays, the ladies are close friends and even double date with their S.O.'s, Prince Harry and David Foster.
Ansel Elgort & Timothee Chalamet
As teens, the actors both attended the famed LaGuardia High School in New York City together. Just a few years later, the up-and-comers were both nominated for acting awards at the 75th Annual Golden Globe Awards.
Cameron Diaz & Snoop Lion
The comedic actress and rapper attended Long Beach Polytechnic School, a California high school well regarded for their football program. Cam has mentioned she's "pretty sure" she bought pot from Snoop back in the day.
Zach Braff & Lauryn Hill
New Jersey's Columbia High School had a mix of comedy and music skills with this talented duo.
Lady Gaga & Nicky Hilton
Both stars attended Convent of the Sacred Heart, a Roman Catholic all-girl school in New York City. Paris Hilton also attended but didn't graduate.
Tupac Shakur & Jada Pinkett Smith
It's such a small world! The famous rapper and actress both attended Baltimore School of the Arts.
John Krasinski & B.J. Novak
Before co-starring together in The Office, the Boston area's Newton South High School classmates starred in the same school play.
Claire Danes & Morena Baccarin
Speaking of co-stars, these two Homeland actresses went to the same New York middle school before making it big. What a way to keep in touch!
Charlie Sheen & Rob Lowe
Both Hollywood actors began their friendships at the same high school in Santa Monica, Calif. At the time, Lowe wanted to get into theater, while Sheen hoped to become a baseball player.
Sean Penn & Robert Downey Jr.
The two A-list actors enjoyed their school days by the beach at Santa Monica High School.
Adele & Jessie J
Talk about a talented class! Both Adele and the "Domino" singer attended BRIT School for Performing Arts.
Rachael Leigh Cook & Josh Hartnett
Before she became a celeb mom and he became a famous actor, the duo were simply school friends at Minneapolis South High School.
Ed Helms & Brian Baumgartner
It's not every day you see classmates from years ago reunite on a network show. Lucky for these two, the Westminster High School alumni came together on The Office.
Kate Hudson & Liv Tyler
Even with a two-year age difference, the Hollywood actresses were able to attend Santa Monica's Crossroads School for a brief time together.
David Duchovny & John F. Kennedy Jr.
Before his untimely death in 1999, the famous politician shared a classroom with Duchovny at New York's Collegiate School.
Jay Z & Busta Rhymes
Let's hear it for New York! The famous rappers both attended George Westinghouse High near Brooklyn.
Anderon Cooper & Christian Slater
Before acting onscreen or covering wars for CNN, the twosome attended class together at New York's Dalton School.
Matt Damon & Ben Affleck
Long before they co-wrote and starred in Good Will Hunting together, the Hollywood actors were good pals at Cambridge Ridge and Latin High School in Boston.
Barbra Streisand & Neil Diamond
How talented was this school?! The established singers perfected their talents at Erasmus Hall High School in Brooklyn.
Neil Patrick Harris & Freddie Prinze Jr.
The comedic actors were the life of the party at La Cueva High School in Albuquerque, New Mex.
John Cusack & Jeremy Piven
In addition to living across the street from each other, the two actors also attended Evanston Township High School in Evanston, Ill. They both also studied under Piven's parents, Byrne and Joyce Piven, famous acting teachers.
Nicole Kidman & Naomi Watts
Before they moved to Hollywood, the Australian actresses were pals at North Sydney Girls' High School.
Jennifer Aniston & Chaz Bono
Talk about a surprise pairing! The Friends star attended LaGuardia High School of Performing Arts with Cher's child.