— On stage and off, you don’t want to tangle with Joyce DiDonato — American soprano extraordinaire and practiced kickboxer, too.

The 45-year-old diva has been leaving audiences at the Royal Opera House in Covent Garden roaring for her singing and performing of the hugely demanding bel canto (beautiful singing) role of the doomed Queen Maria Stuarda — Mary Queen of Scots — in the second of Gaetano Donizetti’s three Tudor operas.

There’s hardly a more gripping and dramatic scene in opera than the one at the end of Act II when DiDonato as Maria has a knock-down, drag-out confrontation with Queen Elizabeth I, sung by the up-and-coming Italian soprano Carmen Giannattasio.

They spit insults at each other, DiDonato hurls “vil bastarda” (evil bastard) at her rival and pulls the tablecloth from under Elizabeth’s picnic lunch, sweeping all the food and dishes to the floor — all this in the full knowledge that it will ensure she has her head chopped off.

“I feel completely shattered,” DiDonato, changed out of her 16th-century-style royal frock and into a cocktail dress, said after the opening night this month.

“This is the most difficult role I sing, so I always have to step back a bit and make sure I’ve got some bit of me that is engaged just in navigating the vocalizing . . . but there are two moments when I just lose it and I’m really not present anymore, and one of them is the confrontation scene,” she said.

Otherwise DiDonato — who practices the martial art of kickboxing to keep fit and shows off her arm muscles to prove it — thinks that in this production she has finally nailed a role she has also played at the Houston Opera and at the Metropolitan Opera in New York.

“The first time, in Houston, the part was ‘singing me’ kind of from beginning to end, but I got through it. I did a lot of work and when I got to New York, I’d say there was about 16 percent of the opera that was still ‘singing me’ and at some point I just had to get through those particular moments.

“Here I finally feel like now it’s mine. I’m choosing in every moment how I want to sing it rather than this is the only way I can do it, and I’ve never felt that with another role. This has been the biggest learning curve for me.”

— Reuters