Both clubs have confirmed that the 54-year-old centre-forward who played for Everton over a hundred and fifty times, has passed away shortly after being diagnosed with an unspecified illness.
Campbell was arguably one of the most important individuals to wear the famous royal blue shirt in recent decades as his contribution to keeping the Toffees up in the 1998-99 season was absolutely critical.
When the former Arsenal and Nottingham Forest striker arrived at Goodison Park in April 1999, the Blues were once more fighting for their lives as relegation loomed yet again.
In what has become a seemingly never-ending theme, questions about the club's future and another season of struggle on the pitch, had seen Walter Smith's side slide down the Premiership table.
All the momentum seemed to be taking them down after so many near-misses in the nineties and two last-day survival sagas. Nothing changes! .
I remember his signing well and although there was some uncertainty about whether he could still score goals in the English top flight after an unsuccessful spell in Turkey, Campbell soon disproved any doubters wrong.
He scored nine times in five matches, including a hat-trick in a six nil demolition of West Ham United at the Grand Old Lady, as the Toffees survived with a week to spare.
Then, the Londoner cemented his place in Everton folklore as he netted the winner at Anfield in the first derby of the following campaign. I still vividly recall watching that game in a pub in Liverpool.
That of course, remained the last time the Blues had won at the old enemy, until Carlo Ancelotti's side triumphed two nil in the 2020-21 season.
However, Ancelotti's victory was slightly bitter-sweet as there were no fans at the ground to enjoy the occasion, unlike in '99.
In total Campbell scored fifty-one times for the Toffees before eventually moving on to West Bromwich Albion whom he also helped survive relegation too.
Few players before or since can have made such an immediate and decisive impact as Campbell did when joining Everton. It is almost certain that if he had not signed, the club would have gone down that season.
And he joins that long list of outstanding Blues centre-forwards such as Duncan Ferguson, Graeme Sharp, Bob Latchford and down to Tommy Lawton and the great Dixie Dean, who have gained legendary status at Goodison Park.
Rest In Peace, Super Kev.