It's strictly betting fever

More than 20 million viewers will tune into the reality TV clash of the year tomorrow night when Strictly Come Dancing takes on The X Factor.

ITV1's pop talent show and BBC1's celebrity dance contest both reach their grand finals and experts predict that about £3 million will be gambled on the outcomes.

The hot tip to win Strictly Come Dancing is former Olympic hurdler Colin Jackson, with odds of 4/6.

Judges have described his dancing as "bootylicious" and he and his partner Erin Boag are widely predicted to beat DJ Zoe Ball and cricketer Darren Gough.

Meanwhile, 21-year-old ex-shop assistant and teenage heart-throb Shayne Ward, from Manchester, is 4/7 favourite to take The X Factor title, ahead of duo Journey South and former Enfield binman Andy Abraham.

Rupert Adams, a spokesman for William Hill, said: "Early indications are that £3million will be placed on the outcome in the final two days. It is going to be a massive weekend.

"We think that the reason so many people are betting this year is because it is so close and everybody has a different theory about who will win which show and why. Usually on these shows there is a clear favourite and the odds become so short they are prohibitive.

"The worst scenario for bookies is for the two favourites, Colin and Shayne, to go on and win but we feel confident that there will be an upset in at least one of the shows.

"There is a random selection of people gambling on Strictly Come Dancing. They are betting anything from £10 to £50.

"The people betting on The X Factor are very much like the people who are voting on the show, predominantly females aged 20 to 30. Our biggest bet so far was £5,000, for Shayne Ward."

Online betting firm Betfair exposed a five-man gang that had made more than £100,000 by betting on the outcome of reality TV shows including The X Factor.

The other big competition is for viewing figures. Tomorrow night marks only the third time that the rival shows have gone out at the same time and on both previous occasions Strictly Come Dancing surged ahead, with 9.4 million viewers compared with The X Factor's high of 7.5 million, achieved last week.