Gessle formed the Swedish band with Fredriksson in 1986 and went on to achieve international success in the late 1980s and early 1990s as chief songwriter of hit singles “It Must Have Been Love” and “Listen to Your Heart”.
Frediksson’s family announced the singer’s death in a statement, which read: “It is with great sadness that we have to announce that one of our biggest and most beloved artists is gone.”
Writing on Twitter, Gessle, 60, said: “Things will never be the same.
He wrote: “Time goes by so quickly. It’s not that long ago we spent days and nights in my tiny apartment sharing impossible dreams. And what a dream we eventually got to share! I’m honoured to have met your talent and generosity.”
Gessle sent his love to Frediksson’s family, including her husband Mikael Bolyos and their two children, Inez Josefin, 26, and Oscar, 23.
Fredriksson has been suffering ill health ever since she was diagnosed with a brain tumour after fainting at home in 2002.
She continued to record music as a solo artist and scored her first number one single in Sweden with the song “Där du andas” in 2009.
Fredriksson reformed Roxette with Gessle and went on a worldwide tour in 2010.