The Ladbrokes customer has put the money on the line clearly confident that the N-Dubz star will triumph in next week's final.
The N-Dubz rapper has been subject to the biggest gamble of the series so far, and the wager has forced the bookies into slashing his odds of winning to just 7/2, which makes him the new second favourite.
Jim still leads the betting at 6/5 but it would be a huge shock if he's evicted on Wednesday night as the 20/1 outsider, with Liz Jones the odds-on favourite to go.
Jessica Bridge of Ladbrokes: "We think this punter's Dappy to place that much money on the N-Dubz star.
"Jim's still the clear favourite so it's hard to see Dappy causing an upset."
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