Every opera singer has his or her pre-show traditions. For Norwegian tenor Thomas Ruud, he must eat a big, heavy steak as ballast before every performance. "If I haven't eaten, I struggle."

Ruud, 50, will be singing the role of Radames in the Singapore Lyric Opera (SLO) production of Giuseppe Verdi's Aida at the Esplanade Theatre in June.

The popular 19th-century opera follows the star-crossed romance between Radames, the Egyptian captain of the guard, and his captive Aida, who is an Ethopian princess. The Egyptian king's daughter Amneris is also enamoured of Radames, who must choose between his loyalty to his country and his love for Aida.

The $1-million, 100-strong production, which will be directed by Australia-born Andrew Sinclair, is one of the biggest productions the SLO has mounted since Turandot in 2008.

Ruud, who was in Singapore last month to perform at the SLO's Opera Ball, tells The Straits Times that the role of Radames is one that can trip up even an experienced singer.

The challenge, he says, is one of pacing. "You start very heavily, with passion and power, and then at the end of the opera, you have this sweet and soft duet. It's like running 50km and then suddenly you have to jump instead."

While many operas leave some leeway for the singer to warm up, Verdi placed the big aria Celeste Aida early on, which presents the tenor with a dilemma. "Either you have to warm up so much to sing Celeste Aida that you will be tired during the performance, or you save your voice and have no time to sing yourself into the role."

He has sung the role twice before - but in the 1990s and not in a full production. "I have had to study it all over again as the muscles in the body change."

He looks forward to the chance to tackle the role from a more mature perspective. "Verdi wrote Aida for an older voice, a bigger voice. Back then, I was too young to sing it."

He is one of two international opera stars who will be sharing the role of Radames, the other being Spanish tenor Israel Lozano.

Singaporean soprano and SLO artistic director Nancy Yuen will share the title role with South Korean soprano Jee-Hye Han. Yuen has sung the role with Dublin Opera and Kentish Opera in Britain. Grace Echauri from Mexico and Jopei Weng from Taiwan will sing the role of the Egyptian princess Amneris, while Italy-based Singaporean baritone Martin Ng will play Aida's father, the Ethopian king Amonasro.

Ruud, who is single, has been singing since he was six. "If I don't sing, I feel like I haven't showered."

He made his debut with the Norwegian National Opera in 1994 as Count Almaviva in The Barber Of Seville, a role he has reprised in more than 150 performances.

Since then, he has sung lead roles in operas such as Faust, Madame Butterfly and Tosca. In 2011, he performed in concert with the legendary New Zealand soprano Kiri Te Kanawa.

"It's important to study a role so well that you can sing it whether you're in good shape or not," he says. "(American soprano) Renee Fleming once said, 'I have only been in good voice once in my life and on that day, I didn't have a performance.'"

Yet, in the professional opera singer's life, emergencies are rife. Two weeks before speaking to ST, Ruud was flown in at the 11th hour for a production of Carmen in Norway because the tenor had fallen sick. He sang from the orchestra pit while the man pretended to sing onstage. "That was difficult because I hadn't sung the role for quite a while and it was in Norwegian, the text of which I had never studied."

But that is how it is, he says. "Even if they wake you up in the night to do it, you have to be able to sing."

Correction note: An earlier version of the story stated that Nancy Yuen will be performing with Iman Moustafa. The line-up has since been changed due to a scheduling conflict on Iman Moustafa's part.