Katy Sullivan in ‘Cost of Living’ (Photo by: Jeremy Daniel).

“Cost of Living” was a groundbreaking play when it first debuted Off-Broadway at Manhattan Theatre Club. Now on MTC’s Broadway stage, the Pulitzer Prize winner by Martyna Majok continues to ignite important conversations about relationships and how people care for each other.

In the latest episode of “The Broadway Show with Tamsen Fadal,” one of the production’s four stars, Katy Sullivan, chats with Paul Wontorek about her six-year journey with the play and why the opportunity terrified her at first.

“Cost of Living” tells the story of two couples: one a former husband and wife, the other a grad student and his new caregiver. The play also looks at the relationships between abled and disabled people.

Sullivan is one of two actors with disabilities playing characters with disabilities. She’s joined onstage by Gregg Mozgala, who has spastic cerebral palsy and who plays John, a character with the same disorder.

Sullivan’s character, Ani, is quadriplegic and bound to a wheelchair following a devastating accident. While that’s not Sullivan’s personal story, the actor has used prosthetics to walk since she was a year old, as she was born without the lower halves of her legs.

For the production, Sullivan learned to use Ani’s wheelchair while balancing the other requirements of the role and of being onstage in general.

“It is way more complicated and way harder than it looks to have all of this going on — all of this emotion, volume to fill a house — and remain perfectly still,” she told Wontorek.

While Sullivan has been with the show since its start, she didn’t initially think the play would wind up on Broadway.

“What I did think when I got the script is how unbelievably authentic, groundbreaking and real it was,” she told Wontorek.

Upon reading the script, she thought, “This is terrifying. I should probably do it.”

Sullivan said her character Ani has “been through the gauntlet of life experience.” To Sullivan, Ani is neither a hero nor a tragedy, which, she says, has been the case with many of the roles she’s tackled in TV and film.“To get this three-dimensional character who’s flawed, who’s angry, who’s not looked at as a victim or a hero was extraordinary,” she said.

Hear more from Sullivan in this week’s episode of “The Broadway Show,” which also features “& Juliet” cast member and Tony Award winner Paulo Szot discussing his role as a parent in the show as well as the fun he’s having onstage. Viewers can also catch glimpses of “KPOP” and “A Beautiful Noise, The Neil Diamond Musical,” both new musicals set to open later this fall, as well as the new national tour of “Les Miserables.”

“The Broadway Show with Tamsen Fadal” airs on weekends. Check your local listings for air time and channel.