A middle-aged woman, buried to her waist in rubble with an open parasol held high, happily chatters away about another happy day; it’s one of the more iconic images of 20th-century theater. The play is Samuel Beckett’s “Happy Days,” which opens tomorrow at the Brooklyn Academy of Music, and if it is slightly less familiar to theatergoers than Beckett’s seminal work, “Waiting for Godot,” it is still every bit as riveting, testing the mettle of ambitious actresses since its premiere in 1961. Never mind the torrent of words to be mastered by the actress playing the half-buried Winnie (husband Willie does occasionally emerge from his hole for a few grunts, but the piece is virtually Winnie’s monologue). It’s the play’s physical restrictions that make the enterprise so grueling, and things only get worse in the second act, when the level of earth rises to Winnie’s neck.

Enter the famed Irish actress Fiona Shaw, once again teaming up with her longtime collaborator, director Deborah Warner, to tackle Beckett’s modern classic. New York theatergoers may have caught the pair’s “Medea” at BAM in 2002 or, in 1996, their stunning reading of Eliot’s “The Waste Land.” Lucky visitors to London in 1995 may have seen Ms. Warner’s remarkable “Richard II” at the National Theatre of Great Britain, with Ms. Shaw in the title role. The current production of “Happy Days” is also from the National Theatre, and will be visiting BAM for four weeks onstage.

After performing “Happy Days” last November at the Kennedy Center in Washington, Ms. Shaw was recently back in London, chatting away on the phone about the play, and sounding every bit as chirpy as Winnie. There was a time, however, when the days were not so happy. Consider first Ms. Shaw’s and Ms. Warner’s problematic history with Beckett: Their 1994 production of Beckett’s “Footfalls” was shut down by the Beckett estate, infamous for keeping a careful eye on all productions, for certain liberties taken with the staging. “It was unfortunate at that time,” Ms. Shaw mused, “but I think what went wrong was that Beckett was very recently dead, and I think a lot of people were very protective of every aspect of him. I don’t think the same thing would have happened now, if the same production was on.”

As it was, things were smoothed over through discussions with the executor of the estate and the playwright’s nephew, Edward Beckett. But then came the question of what other Beckett play to do. When “Happy Days” was suggested, Ms. Shaw was somewhat aghast. Besides feeling she was too young for the role, she found the play’s notorious physical difficulties worrisome. For an actor famous not only for her emotional intensity, but also for a vibrant onstage physicality, the prospect of performing half-buried was less than appealing. “It was terrible! Awful!” Ms. Shaw remembered. She recalled her rehearsal period. “I spent the winter sitting up in the middle of these sandbags and getting up every half hour to play badminton and keep warm and not lose all sensation in the arms and legs!” But, she added, “I’ve gotten very used to it now. I actually quite like it. And I find my body goes to sleep except for my head.” Ms. Shaw’s infectious good humor when talking about the play is also essential to her interpretation of it. She appears genuinely concerned that audiences not fall prey to the inaccurate cliché that Beckett is bleak and depressing, and critics have noted, among other things, how funny Ms. Shaw’s Winnie is.

More than just a question of the role of comedy in general, what’s key is the effect of an audience’s laughter and its relation to the communal quality of the best theater experience. A year ago, Ms. Shaw wrote in the British press about the unexpectedly liberating effect of the audience’s laughter, which she felt from the very first moment of the play’s first preview performance. Now, she expanded on the idea: “It’s very gratifying to have the audience laugh, because they laugh not at it, but with recognition of it,” she said. “Beckett seems to have given us permission to feel those things, and there’s something quite comforting about that.”

But perhaps her interpretation should not be surprising, as one of the playwright’s hallmarks is his ability to perfectly fuse comedy and tragedy. As Ms. Shaw put it, “In some ways, he is the son of Shakespeare, because he’s done this astonishing thing of making the thing funny and unspeakably bleak. I mean, he’s not a man whose view of the world I would follow, and I don’t think he thinks there’s much hope for any of us. But what he does do is give us the joy of celebrating that we are what we are.”