Rovers fans were stunned to see the prince in the directors box donning a blue and white scarf during their side's drab 0-0 draw with Newcastle United.
When asked if he was a Rovers fan pre match, the prince replied: "I am now. And for the next few hours".
Even following a disappointing 90 minutes, the 52-year-old ruler of Monaco, told the Lancashire Telegraph: "I'm sorry it wasn't a better result. A bit of a scrappy game and a few bad calls but an enjoyable day all the same."