It's tough to make friends, but even more so in Hollywood. The show business is littered with fake friendships. Who else can you trust to be your truest friends than the ones you have known before you became a big star? Arguably the most famous childhood-friends-to-Hollywood-stars story is of Matt Damon and Ben Affleck who got their big break together with Good Will Hunting, which they co-wrote and co-starred in. Here are some more celebrity duos that you might not have known were joined at the hip before their becoming big industry successes. 

Nicole Kidman and Naomi Watts
Celebrity Childhood Friends - BookMyShow

These Hollywood actresses have been best buds since they were 13 years old. How? They went to the same school in Australia. Despite having busy lives and not living in the same city these days, they still catch up regularly and are most certainly friends for life. 

B. J. Novak and John Krasinski 
Celebrity Childhood Friends - BookMyShow

B. J. Novak and John Krasinski starred together in The Office, but they already knew each other since their school years and used to play in the Little League together. Novak has also joked that he would wake up one day and realize the Office was a dream and John was in it, but everybody called him Jim.

Adam Levine and Jonah Hill
Celebrity Childhood Friends - BookMyShow

These two have grown up together and are almost like family. Their fathers met in principal's office in junior high and stayed close over the years and so did their sons. Hill also officiated Adam's wedding to Behati Prinsloo in 2014 and says Adam has been the same, even after becoming famous.

Demi Lovato and Selena Gomez

Selena and Demi had been friends even before Disney, which launched them into the spotlight. They met during an audition for the children's show Barney. They've had some drama between them over the years, but their friendship remains unbreakable. 

Jon Hamm and Paul Rudd
Celebrity Childhood Friends - BookMyShow

They have been friends long before they became famous actors. Rudd reminisces about them being rivals, fighting over the same girl in college. Hamm moved out to L.A. after seeing Rudd in Clueless. They reconnected and are now the best of friends.

Rami Malek and Kirsten Dunst 
Celebrity Childhood Friends - BookMyShow

The Mr. Robot star, Rami Malek went to the same high school as Kirsten Dunst. He even had a crush on Dunst, who graduated a year later than he did. They never got together, but Dunst is now dating Malek's friend, Garett Hedlund. 

Tobey Maguire and Leonardo DiCaprio 
Celebrity Childhood Friends - BookMyShow

Two young boys interested in acting met during an audition in the 80s and recommended each other for roles. Years later, they are big stars of Hollywood and who have been friends for more than 25 years. They're often seen hanging out together and share a love for basketball. 

Which of these celebrity childhood friendships came as a surprise to you? Let us know in the comments.