The Hollywood pair are both huge fight fans and are no stranger to sitting cageside for the UFC.
Guardian of the Galaxy’s Pratt was all smiles dressed in a black shirt as he took his place in the arena.
As was Facebook boss Mark Zuckerberg, who was even in talks recently to fight Twitter owner Elon Musk.
Zuckerberg took his passion for martial arts to new heights in February when he cornered former featherweight champion Alexander Volkanovski.
But the social media mogul was instead just watching the night’s action alongside UFC boss Dana White and Leto.
Other sports names included NFL pair Maxx Crosby and Kyler Murray as well as women’s basketballer Kelsey Plum.
But perhaps no bigger name in the crowd was boxing icon Tyson, a close friend of White.
Tyson – who in 1986 became the youngest heavyweight champ of all time aged 20 – is in training to fight YouTuber-turned boxer Paul.
The controversial clash between Tyson, 57, and Paul, 27, is set for July 20 in Texas and has been scrutinised over the 30-year age gap.
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US politician Vivek Ramaswamy – who recently withdrew his 2024 Republican presidential campaign – was also pictured with White.