It is one of the fiercest rivalries in football, and on Sunday millions of people will watch the Tyne/Wear derby with an intensity reserved only for that fixture.
So what do you do if the person you fall in love with supports the opposing side?
Kirsty Cummings, 40, from Fishburn in County Durham, cannot remember a time when she did not support Sunderland.
"My dad was a big fan, he took me under his wing and he just got me hooked for life," she says.
A Sunderland season ticket holder, she met husband Steven before realising he supported her team's greatest foe - Newcastle United.