If we've learned anything from previous seasons of Only Murders in the Building, it's that almost anything can be a clue.

In the sixth episode of Season 3, the (already very stacked) cast got a boost from two very notable, very amusing cameo appearances: Matthew Broderick as a potential musical replacement for Charles (Steve Martin), and legendary actor and filmmaker Mel Brooks, who appears briefly for a very entertaining video call with Oliver (Martin Short).

SEE ALSO: 'Only Murders in the Building' Season 3: Who are the main suspects?

But are these cameos simply comic fodder or have they been intentionally included to give us a clue as to the identity of the murder(ers)? We've recapped what happens in Season 3, episode 7, and how it could tie in to a theory about who Ben Glenroy's (Paul Rudd) killer is, below.

What happens in Only Murders in the Building, episode 7?

Following a nasty argument at the end of episode 5, our beloved podcast trio is in tatters. Nobody's speaking to one another, Mabel (Selena Gomez) is running her own investigations, and Oliver has gone as far as attempting to recast Charles' role in the Death Rattle musical. This is proving difficult until Clifford (Wesley Taylor), Death Rattle's producer, along with his co-producer mother Donna (Linda Edmond), manages to persuade "friend for life" Matthew Broderick to audition.

Why are Donna (Linda Edmond) and Clifford (Wesley Taylor) pushing Broderick so hard? Credit: Patrick Harbron/Hulu

"When Cliff called, I just dropped everything," says Broderick, nailing the audition — namely, the "Pickwick Triplets" patter song Charles has been struggling with — before obsessing over his new character's every tiny little detail. It doesn't take long before Oliver, realising Broderick's perfectionism means they'll never get anything done, has a video call with Mel Brooks, who cast Broderick in the 2001 musical adaptation of his classic 1968 movie, The Producers (Broderick also went to star in the movie's 2005 remake with Nathan Lane, who stars in Only Murders in the Building).

"Did you have any problems working with Broderick?" asks Oliver. "I'm working with him on something now, and—"

"Oh my God! You didn't tell him in any way you were open to his ideas, did you?" ask Brooks.

"Well I might have told him he could—"

"Oh Oliver," cuts in Brooks, shortly before ending the call. "You're fucked!"

What clues do the cameos give us?

With the cameos from Broderick and Brooks, The Producers is front and centre of our minds in episode 7. Oliver even mentions the musical at the start of his video call with Brooks, apologising that he never got around to seeing it. It'd be easy to think of these things as nothing more than comic throwaways — more high-powered stars popping in for fun walk-on roles on the third season of a hit show known a fair few of those. But what if it was something more than that?

The clue, in my opinion, lies in the plot of The Producers itself.

The story follows an ageing actor and his accountant as they attempt to make some fraudulent money by putting on a show that's doomed to fail. The idea is to oversell shares, make a production that's as bad as possible, and then — when the IRS fails to investigate, assuming the flop has lost money — keep the cash of those who invested.

Wildly, this is a still from "The Producers," not "Only Murders in the Building." Credit: Andrew Schwartz/Universal/Columbia/Kobal/Shutterstock

What if this story, which gets such a strong callback in episode 7, is actually a clue to the identity of the person (or persons) responsible for Ben's death? What if Only Murders in the Building Season 3 is actually its own version of The Producers, and Death Rattle's financiers Donna and Clifford have been trying to make a flop all along as part of some money-making scheme? Could they have found a way to kill off their show's main star on opening night, just to guarantee it fails?

When you zoom out, the theory starts to make more sense. Why else would they have hired Oliver Putnam, whose last show was a notorious flop, for instance? And why would Clifford have pushed for Broderick to replace Charles, given that he's clearly a nightmare to work with? A lot of the pieces seem to tie together. But if that is the case, are both Donna and Clifford involved, or is it only one of them? And what's their motive for needing all that money so desperately? Could Clifford be in some sort of financial trouble that Donna has set out to fix?

Time will tell.

How to watch: Season 3 of Only Murders in the Building is now streaming on Hulu.