By this point, just about everyone on the planet knows that Taylor Swift and Calvin Harris are broken up, and the former has moved on to a remarkably fast-moving relationship with Tom Hiddleston.
But it's still not clear exactly why Swift and Harris called it quits.
Fortunately, TMZ is basically what you'd get if Sherlock Holmes was willing to pay sources, and the site claims to have figured out the cause of Taylor and Calvin's unexpected split.
Despite reports to the contrary, insiders say Taylor never cheated on Harris with Hiddleston, but the couple didn't just gradually grow apart, either.
There was a definitive breaking point - and surprisingly, it came as a result of Taylor helping Calvin out with a song.
Sources say Calvin's latest single, "This Is What You Came For", was co-written with Taylor, but at the time the new couple didn't want anyone to know they'd collaborated for fear of overshadowing the song.
In fact, the club hit reportedly sprang from a melody that Taylor came up with, recorded on her iPhone, and shared with Calvin.
Despite arguably being the primary creative force behind the song, Taylor didn't want to be mentioned in any of the promotional material.
Instead, Taylor adopted a pseudonym, Nils Sjoberg, for her co-writing credit.
Despite her apparent selflessness in giving Harris sole rights to the song, however, Taylor was reportedly blindsided when she saw this:
That's a recent interview with Ryan Seacrest in which Harris says he and Taylor "haven't even spoken about collaborating."
This, despite the fact that at that point, they'd already written "Came For" together.
Sources say Calvin went too far in his denial, and Taylor's feelings were hurt.
A few days later, Taylor attended the 2016 Met Gala by herself, where she danced with Hiddleston.
The rest, as they say, is history.