"I rarely shave, except during my holidays. But for this role, it's perfect to keep my beard," Placido Domingo says at a recent interview at the National Centre for the Performing Arts in Beijing.

He's talking about his role as a monk named Athanael in the three-act opera, Thais, the first operatic production to be staged by the NCPA in 2018, running from Feb 2 to 6 at the venue.

"Athanael keeps walking through the harsh desert and I guess he has no way to shave," adds Domingo, who arrived in the capital in the early hours of Jan 27, before joining rehearsals later that same day.

Written by French composer Jules Massenet, and with the libretto adapted by fellow Frenchman and dramatist Louis Gallet, the opera was inspired by an old French novel by Anatole France, who won the Nobel Prize in literature in 1921.

The opera premiered in 1894 in Paris, and the story follows the journey of Athanael, who lives in 4th-century Alexandria, Egypt, and tries to convert a courtesan called Thais to Christianity, only to find himself succumbing to her charms.

This will be the fourth NCPA opera that Domingo has joined. The veteran Spanish singer has been performing in NCPA opera productions since 2010, including Giuseppe Verdi's Nabucco and Macbeth.

"While expanding my repertoire, I have performed operas by composers from all around the world, such as Italian, Russian and German composers. Operas by French composers are among my favorites and Thais is one of the best operas in the world. It has some of the most beautiful arias," says 77-year-old Domingo, who is often described on the international stage as "the King of Opera" and has sung 148 roles in more than 3,900 performances.

Domingo, who has switched from tenor to baritone roles in the past few years, says that Athanael is a great role for baritone. That's why he loves performing the role again and again.

In 2014, he performed the role in the Los Angeles Opera's production of Thais. Later, he performed the role in other versions of Thais at the Salzburg Festival in 2016 and at the Barcelona opera house, the Gran Teatre del Liceu, in 2017.

Patrick Fournillier, a Massenet specialist, who conducted the Los Angeles Opera's production of Thais in 2014, will take the baton for the NCPA production in Beijing by performing with the NCPA orchestra and chorus.

"For a long time, Thais was one of the most popular operas. But from the middle of the 20th century, it slowly sank into oblivion," said NCPA opera consultant Giuseppe Cuccia in an earlier interview with China Daily.

But in recent years, the work has witnessed a revival, with many major opera houses including it in their repertoire once again.

In the NCPA version, two sopranos－Ermonela Jaho from Albania and Davinia Rodriguez from Spain－will play the role of Thais. Both have collaborated with Domingo in other operatic productions.