Initially, they weren't interested in meeting each other - but they hit it off right away

Bill Gates and Warren Buffett are the second and third-wealthiest people on the planet. They also happen to be best friends.

But when they met 27 years ago, it was grudgingly. Each one was surprised at how much they enjoyed talking to the other

Since then, they've been a tag team on political and philanthropic causes as well as mutual mentors. Plus, they love goofing off together

Warren Buffett, 87, is the third-richest person in the world. He's a legendary investor and the CEO of Berkshire Hathaway

Gates' mother, Mary, had invited the late Meg Greenfield, a Washington Post editor, to her home

In fact, in 2014, Buffett donated more than $2.1 billion to the Bill and Melinda Gates Foundation

That same year, Gates and Buffett, along with Sheldon Adelson, published a New York Times op-ed pushing for immigration reform