Pietersen’s claim came in the immediate aftermath of Real Madrid’s 3-0 defeat to Barcelona in the El Clasico.
He tweeted: “Ronaldo will be at @ChelseaFC next season…”
Ronaldo was a frustrated figure as Barcelona eased to victory over 10-man Real and extending their La Liga lead to 14 points.
The Portuguese star signed a five-year contract with Real in November 2016 but wants another new deal putting him in the same wage bracket as Lionel Messi and Neymar.
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