Imagine memorising lines, lyrics and dance moves for the lead role in one of the world’s biggest plays.

For the cast of Hamilton, it’s what you sign up for.

The musical, created by Lin-Manuel Miranda, has been a huge hit with audiences and critics since its Broadway debut in 2015.

It retells America’s early political history through jam-packed raps and musical numbers that hurtle through genres including hip-hop, pop and R&B.

Praised for its clever, complex lyrics, cast members sings and dance their way through an estimated 144 words per minute during each show.

Actor Jonathan Hermosa-Lopez says this is why Hamilton is regarded as the “boss level” of musical theatre.

“It’s every single element of theatre at the highest level, put together,” he says.

“The music is so demanding and so relentless in pace.”

And Jonathan should know – he’s had to memorise not one, but four different parts.

The British-Colombian actor is a member of the theatre company currently performing Hamilton on a UK and Ireland tour.

But his road to the show actually started with crushing disappointment.

He was working graveyard shifts in hospitality while trying to find acting work, and was rejected when he first auditioned for Hamilton.

“It was this weird feeling of my life falling apart,” he says. “What else is there for me to do?”

But the following week he got a call, asking him to be an “alternate Hamilton”.

Alternates, or understudies, are the people on standby to step in if a lead actor falls ill or is otherwise unable to perform.

Rather than feel intimated by the scale of the challenge, Jonathan says he embraced the opportunity.

“I sat down for 12 hours in one day, learning it word for word, note for note,” he says.

“It got filmed and sent to the American producers who have the final say on things, and I got the part.”

There’s always a chance Jonathan, who grew up in south London, could have to swap a dressing room for centre stage.

When BBC Newsbeat meets him, it’s hours before he covers the lead role in front of a full house at Birmingham’s Hippodrome.

On this occasion, he knew he’d be needed in advance, but he isn’t always given that luxury.

“I just have to jump into the show,” he says.

Jonathan recalls getting a call from Hamilton’s tour manager during its Manchester run, moments before he was about to take a shower.

He says they asked him to come down from his room immediately as lead actor Shaq Taylor, who plays Alexander Hamilton, might need to come off-stage.

“My whole body flipped,” says Jonathan.

“So I went downstairs and the heads of every department were waiting for me – ready to do my hair, my costume.

“Sound were ready to put my mic on.

“In my mind, I was like, ‘this is the job I signed up for’.

“When Shaq came off there was an announcement and, when the next song started, I was on stage starting the show again.

“It takes a village to run the show but in that moment, it’s me that has to come in and fill those shoes.”

Hamilton’s cast is mostly made up of performers from minority backgrounds playing white historical figures, many of whom forced black people to be slaves.

Others who’ve performed in the show have spoken about it giving them a platform, and Jonathan says getting on stage felt particularly significant for him.

“Living in a single-parent household, I wanted to achieve something to make my mum proud,” he says.

But although his mum was desperate to see Hamilton, Jonathan had to say “no” when she asked to go with him.

He wanted her first time to be one when he was on-stage.

“I debuted in Manchester and she finally got to watch Hamilton live with me playing Hamilton,” he says.

There is also pride in being able to provide a positive reflection of the place he grew up in – a council estate in Brixton.

“This beautiful, vibrant community, full of so much diversity.

“I wanted to do something so out of the norm for Brixton, to go into musical theatre,” he says.

He adds there are many talented people in the area “who don’t get recognised” because of a lack of opportunity to do so in south London.

And while the motto for a job tends to be to “leave everything personal outside the building”, he doesn’t subscribe to that.

“The beauty of this show is you don’t have to do that,” he says.

“You get to come in with your own energy, your own baggage and say how can I take what I have today and use it.”