What is in a name? Usually not much, especially when it comes to naming characters in a book or a movie. But sometimes, when an actress has played a very famous character, the names of the characters now surrounding you can cause a pop-culture conundrum. Which is how Lisa Kudrow's Girl on a Train character switched from Monica to Martha.

Let's let Emily Blunt explain. The star of the upcoming thriller The Girl on the Train appeared on The Tonight Show starring Jimmy Fallon, where she laid out the Friends-related complication caused by the fact that her character is named Rachel, and Lisa Kudrow was playing a Monica. (Not a Phoebe, but still, an issue.) As Blunt recalled, while they were filming a particular scene in Grand Central Station in New York City:

We had about 300 extras, and then we had actual commuters coming into Grand Central who heard on the loud speaker, 'OK, guys, we're going to roll on Rachel.' And then they see Lisa Kudrow walking on, and then they hear, 'Guys, we're going to do a close-up of Monica,' and I saw two people have an aneurysm.

Clearly, the casual commuters in New York City assumed that Kudrow + Monica + Rachel = Friends Reunion! Alas, this wasn't the case. The Girl on the Train is an adaptation of a bestselling novel by author Paula Hawkins, and not a back-door effort by David Crane and Marta Kauffman to get their beloved NBC sitcom back in front of the world. Though we'd be lying if we didn't admit that we've been saving that seat on the couch at Central Perk for the Friends cast should they decide that they wanted to reunite. We'll be there for you, guys.

That had to be a pretty funny day on set, though, with the New York City commuters looking around for Jennifer Aniston and Courteney Cox, and only finding Emily Blunt. Boo hoo. This explains why, if you ever have a "Jerry" in your script, there's no way you can put them opposite a "George" or an "Elaine."

However, now that Lisa Kudrow's The Girl on the Train character has been changed to Martha, does that mean she's instantly best friends with Batman and Superman?

The Girl on the Train opens in theaters on Friday. Friends is probably on TBS as we speak.