Mariachi band performs in Julio Cesar Chavez Jr's dressing room before Jake Paul clash

Julio Cesar Chavez Jr. warmed up for his much-anticipated fight with Jake Paul with the help of a mariachi band performance inside his locker room. 

The 39-year-old Mexican, whose father and namesake is one of the greatest fighters of all time, took on the YouTuber-turned-boxer in Anaheim on Saturday night.

As Chavez Jr. went through his final preparations in California, cameras were allowed inside his locker room.

And in the minutes before the first bell, a five-piece mariachi band began to perform while the boxer was put through his warm-up.

The band then accompanied Chavez Jr. on his walk to the ring, where he was a picture of calm before facing the YouTuber-turned boxer.

When asked before the fight why he was so relaxed, the 39-year-old said: 'Why not?' 

'I'm here, it's what I want in my life and that's why I'm super happy. And I think it's better to stay relaxed than feel pressure.

'This is exactly what I've worked very hard for. I'm more prepared, my dad has been here before, my mom has been here before. So this is nothing new. 

'I've worked hard. I'm very excited to be back. This is what I love to do. I'm very calm right now but once I step into the ring, he better hold on.'

But Paul also showed few signs of nerves before the fight. He was spotted dancing alongside his brother Logan inside his locker room.