It’s one thing to have your name up in lights in front of the theater.

But inside, too?

And yet, that’s how THE ROOMMATE starts.

As Mia Farrow and Patti LuPone walk on stage together, their actual real-life names are flashed above them in letters that may be six feet high.

It’s a way of saying, “Let’s get the entrance applause out of the way and get into the world of the play.”

It’s often worth getting into. Jen Silverman’s comedy could be called a comedy-mystery, because there are quite a few mysterious secrets that both Sharon (Farrow) and Robyn (LuPone) have.

A character’s withholding information from another character (and the audience) is a time-honored playwriting convention, but Silverman is that rare playwright who knows how to calibrate her tiny reveals at the correct intervals.

It starts in a large house in Iowa, where Sharon now lives without her husband and son. Both left her for new adventures, so perhaps out of loneliness as much as the desire to save some money, she’ll take in a roommate.

What’s surprising and unbelievable is that Sharon never brings up money – not once. You’d think Sharon would, given that she works at a gift shop, and only on Thursdays. How much can that bring in?

Well, guess that’s why she needs a roommate.

As for Robyn’s source of income, let’s just say that she has some savings.

Sharon certainly didn’t expect that a Bronx native would be her boarder, but feisty and urban Robyn is the one she gets. And why would Robyn choose Iowa? Her grandmother hailed from The Hawkeye State, and that was enough for her to choose it as a place where she could start anew.

Robyn wants to leave her past so far behind her that even if she were to look back, she wouldn’t be able to see it.

Fine, but Robyn has kept certain items that are solid and incontrovertible reminders and evidence of her sordid history. Considering that she wants to make a fresh start, why has she kept these items that could reveal her shameful activities of yore?

The answer, sad to say, is that “So Sharon can search through Robyn’s belongings and find that incriminating evidence that finally gets the plot in motion.” Would that Silverman could have found a better way.

Surprising, too, that Robyn – especially played by LuPone, who’s infamous for having the shortest of fuses – isn’t more furious when she discovers that her luggage has been invaded.

Silverman, though, has a solid and believable theme that she delivers very well. Just as we hear that many people are just one paycheck away from homelessness, certain people are just one person away from encountering someone who’ll inspire them to shed their life-long repressions. In the process, they’ll surprise themselves, live recklessly, and ultimately discover who they truly are underneath.

So, the famous situation known as “City mouse, country mouse” becomes “City rat, country rat.” When it does, THE ROOMMATE ceases to be the innocent fun it’s been. Some who have a solid moral compass will balk at what’s supposed to be amusing. However, Silverman’s skill allows us to hate the sins and not the sinners.

Here’s a question involving designer Bob Crowley. Was it he who decided that Sharon’s wall phone have a l-o-n-g cord? Whoever’s responsible, it’s a fine symbol of how tied down she is.

Speaking of telephones, Academy Award savants will tell you that if a performer has a lengthy scene on the horn, an Oscar often follows. Consideringhow well Farrow maneuvers her phone calls (and everything else), she should at least receive a Tony nomination.

LuPone deserves one, too. All those time-worn complaints about LuPone’s mush-mouthed delivery aren’t in evidence here. Maybe her slurring words are only a problem when she sings, for here LuPone is as clear as Saran Wrap whenever she wraps her lips around Silverman’s excellent words. She’s really funny, too when

Sharon tells Robyn how she spends some of her time. LuPone goes pure Lady Bracknell when she sneers, “Your reading group?!”

Note the italics on reading. Until we get a script in hand, we won’t know for sure if Silverman italicized many of Robyn’s words. But LuPone sure stresses certain ones that make you see that font style on the page.

Finally, both women show such energy that makes them seem far younger than their years.

Jack O’Brien directed solidly, but what may be most remembered from this production is his Playbill bio: “Currently celebrating his Lifetime Achievement Tony Award, but apparently he’s still working.”

Glad that Farrow and LuPone are, too.