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The first eviction vote in the new series of Big Brother opens today with four housemates facing the boot for failing a secret task.

Mario Marconi and Stephanie McMichael were told to pretend to be a couple to hide Mario's real romance with fellow housemate Lisa Appleton.

A fourth housemate, Luke Marsden, was also in on the secret.

Mario, 42, and Stephanie, 19, tied the knot yesterday in what housemates were led to believe was a real wedding ceremony.

But after the wedding breakfast and a Champagne toast, Big Brother interrupted.

"The wedding is now over. Big Brother has a very important announcement - there is a secret couple living in the House. Housemates have one minute to decide who they think those two housemates are," he said.

Housemate Alexandra De-Gale had already said she contested the wedding as "a sham" and, after a group discussion, Michael Hughes announced they thought it was Mario and Lisa.

The correct guess guaranteed that Mario, Lisa, Luke and Stephanie are up for the first eviction and will face the public vote which opens today.

"This has got to be the twist of the century," Michael said after the truth was revealed last night.

Alexandra gave Lisa a hug and told her: "You've done really, really good."

Mario and Lisa were delighted that they no longer had to keep their romance under wraps but Luke was unhappy about being up for eviction.

"The reason why we're on the chopping block now is because of Stephanie," he said.

Stephanie meanwhile jumped into the swimming pool still wearing her wedding dress and told housemates she had found the task so hard she had repeatedly cried in the diary room.

Ladies' man Dale Howard was the first to console her, saying: "At least you can be yourself now."

Many of the housemates had been suspicious about Mario and Stephanie's romance since the start.

Dennis McHugh, Sylvia Barrie, Dale and Alexandra had all been into the Diary Room to tell Big Brother they thought the whole relationship was fake and part of a task.

Alexandra even correctly guessed that Stephanie and Mario were taking part in a secret task which would give them immunity from eviction if successful.

Kathreya Kasisopa, 30, is the new favourite to win the competition, according to Ladbrokes.

The massage therapist has been gambled into 7/2, from 5/1, and displaced previous favourite Michael.

Ladbrokes spokesman Nick Weinberg said: "Kathreya has come from nowhere to seize favouritism. Even at this early stage she looks to be a strong contender for the £100,000 prize fund."

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