Noel Coward was no mystery to director Paul Mullins.

Coward is one of England’s best-known and most-loved playwrights, and Mullins was well familiar with many of Coward’s most popular plays, such as “Private Lives,” “Blithe Spirit” and “Hay Fever.”

But Mullins had never heard of “A Song at Twilight” until Portland Stage Company artistic director Anita Stewart approached him with an offer to direct it. The play opens this week and runs through March 17.

Mullins was intrigued with the offer.

His research revealed that “A Song at Twilight” was one of Coward’s final plays. First produced in London in 1966, he wrote it as part of a trilogy, all set in a luxury hotel in Switzerland. The play depicts an elderly writer whose public image is challenged by a former mistress with secrets to reveal.

Mullins didn’t much care for the other plays in the trilogy, but he loved “A Song at Twilight.”

“I thought this one was really interesting and also very different,” the director said during a rehearsal break at the theater. “It’s a lot like the other things by Coward that we are familiar with, but also very different.”

Because Coward wrote it late in life, there is more reflection and a sense of looking back at a life fully lived. The play is layered with regret for roads not taken, with heartbreak and with a sense of lust.

It could only have been written by someone who had experienced those emotions, as Coward had.

“It just struck me as weighty and with more depth than his other work that we are familiar with,” Mullins said.

“A Song at Twilight” tells the story of Sir Hugo, a successful writer who has managed to keep his homosexuality private. His cover is blown when a former mistress shows up at his hotel to confront him and his wife with his secret past. She has a trove of private letters from Sir Hugo to a man named Percy in which he confides his desires.

It is generally believed that Coward wrote this play with himself in mind. He wrote it during a time when homosexuality was still widely closeted.

Coward never revealed his sexual preference in public until “Twilight” came out, when he said, “It is a subject that only lately has come into circulation, because only lately have we been able to discuss it openly.”

Connecticut-based actor Edmond Genest, who appeared last season at Portland Stage in “Heroes,” leads a cast of four as Sir Hugo. Portland-area actor Maureen Butler plays Sir Hugo’s wife, Hilde Latymer. Carol Halstead portrays the former mistress, Carlotta Gray, and Harrison M. Beck plays the waiter, Felix.

Beck also has the distinction of performing on piano in this play. It’s not a musical, though Coward was also well known for his songwriting. Stewart told Mullins she wanted to incorporate Coward’s music into this show, so Beck finds himself at the keyboard for several songs.

Genest agrees with Mullins — he loves “Twilight” because it feels so personal.

“It was one of his last plays,” Genest said, “and I think because of that, he was a little more honest, as we tend to be when we get older. This has a lot of soul-searching that I hadn’t found in his other plays.”

Genest also loves the language. Coward’s use of words and sentence construction are genius, he said, and on a par with other great playwrights such as Ibsen, Chekhov and even Shakespeare.

“The words are stunning,” he said. “They’re just wonderful to say.”

Staff Writer Bob Keyes can be contacted at 791-6457 or:

bkeyes@pressherald.com

Twitter: pphbkeyes