ESPN lined up the top athletes in the world and ranked them in order of world fame, an exercise to sort through the who's who of celebrity sports figures. 

The formula uses a mix of social media following, Google search information and endorsement deals to rank each athlete, combining the factors to boil it down to who makes it in ESPN's World Fame 100 rankings. 

At the top of the list is global soccer star Cristiano Ronaldo, followed by LeBron James, Lionel Messi, Reger Federer and Phil Mickelson in the top-five. The UFC doesn't have a lot of representation in the list, but three fighters did end up cracking the ESPN's top-100. 

You might think the most famous UFC star right now is Conor McGregor, but that'd be wrong. Ronda Rousey is still the queen of the fight game, with a huge social media following and $8 million in endorsement deals. Rousey comes in at No. 16 on the list. 

She's up to 11.3 million followers on Facebook, 9.5 million on Instagram and 3.4 million on Twitter. That's a huge digital footprint for Rousey, who's also gained fame through her ventures into Hollywood as an actress. Ronda actually moved up almost 10 slots from the 2016 rankings. 

Following her is The Notorious McGregor, who should only see a rise in his popularity if he manages to land his superfight with Floyd Mayweather. McGregor has become a huge star, with a larger than life personality matched only by his incredible fighting prowess. 

McGregor has a massive social media following on Instagram with 11.1 million followers, the place where he really lets his personality pop. He rakes in $4 million in endorsements as well, and clearly The Notorious is doing alright for himself these days. 

Once he gets back into the Octagon, or in the ring, that popularity should only continue rising so long as he continues winning. Expect his No. 25 ranking to see a bump next year. 

The last UFC member to make the list might surprise you. Anderson Silva moved up from unranked to No. 39 in this list, with the famed UFC fighter still holding a special place in combat sports. He's far removed from his best days on top of the championship scene, but he's still wildly popular and recognizable.

The Spider pulls in $8 million worth of endorsements, has 7.9 million Twitter followers, 5.6 million Facebook likes and 7.9 million Twitter follows, earning him the No. 39 slot. 

The UFC once had far more star power than it does today, and only having three fighters in ESPN's top-100 is proof that Dana White has an uphill battle to re-establish the draw power that once thrived in combat sports.