Famous people and drama often go hand-in-hand, but for Jose Mourinho and Taylor Swift, it seems to never leave them alone.
Here's a brief look at some of their worst feuds with the biggest names in sport and showbiz:
Jose Mourinho vs Arsene Wenger
The war of words between the two managers has raged for years - with no sign of settling down - but perhaps the peak insult came from Mourinho in 2005 when he described the Frenchman as "a voyeur".
He was famously quoted as saying: "He likes to watch other people.
"There are some guys who, when they are at home, have a big telescope to see what happens in other families. He speaks, speaks, speaks about Chelsea."
Taylor Swift vs Katy Perry
Exactly what happened between the pair has never been confirmed, but they definitely went from mad love to bad blood.
The rift is linked to reports that Katy's people reached out to some of Taylor's dancers to see if they would perform on her tour instead - which they did. What followed were some angry interviews, shady tweets, and one great pop song.
Jose Mourinho vs Pep Guardiola
These two can add their upcoming Mancunian rivalry to a long list of clashes beforehand, stretching back to 2009 when Barcelona played Inter Milan.
Biggest burn? Probably when the Special One commented on the Bald One's appearance: "When you enjoy what you do, you don't lose your hair, and Guardiola is bald. He doesn't enjoy football."
Taylor Swift vs Calvin Harris
Their break-up went from being civil to a car crash in a matter of tweets. It emerged that Taylor had a helping hand with the lyrics for Calvin's hit This Is What You Came For, which they had apparently planned to keep secret.
Calvin took that as an attempt by Taylor and her team to "bury" him, a la Katy Perry, and told the world on Twitter that he would not be "that guy".
Jose Mourinho vs Rafa Benitez
In case you hadn't sensed a theme with Mourinho's feuds, they tend to last a LONG time - more than 10 years in this case.
The pettiness hit an all-time high in April 2006 when Mourinho refused to shake Benitez's hand after Liverpool beat Chelsea in an FA Cup semi-final, saying afterwards: "Did the best team win? I don't think so."
Taylor Swift vs Kanye West and Kim Kardashian
And finally, the feud of the moment. ICYMI (although it's pretty unlikely you'll have been able to avoid it), Kanye released a song called Famous which included lyrics that the two of them might have sex because he made her famous, but Taylor said she didn't approve those lyrics, but then Kim released a video of Kanye apparently on the phone to Taylor saying she approves the lyrics. Phew.
Taylor's response - "I would very much like to be excluded from this narrative" - has quickly become a go-to quip for real life situations everywhere.
The jury's out for now on who's the worst of these serial feuders - but if Mourinho decides to release a pop song then perhaps that'll clinch it for him.