The former Coronation Street actress, who plays Rosie Trevanion in the ITV drama, told Digital Spy that its two-hour finale "is going to be a shock for everybody".
"It's actually a real tear jerker this one," she said. "So get the Kleenex ready, because it's gonna make you cry.
"[There's] no happy ending. It does have happy moments, but the ending is going to be a shock for everybody. I don't think you'll be expecting it."
Hudson added: "I am so proud of the show. It has gone eight years and people are still wanting it to continue, so I'm glad we've managed to go out there and give it a bit of closure.
"I think it'll be a brilliant high note to end on... I think it's sort of the right time to end it. I would hate for it to finish and people go, 'Oh thank God it's finished, it's been going on too long'."
Hudson also confessed there had been "lots of drunken nights and lots of tears after work" during filming of the Wild at Heart special in South Africa.
"As soon as I got there I couldn't stop crying," she said. "I kept going 'Oh, I'm gonna miss the giraffe', 'Oh, I'm gonna miss the zebra'.
"It was emotional the whole way through, especially the last week. You just had to look at somebody and we'd set each other off."
However, Hudson said that she is now looking forward "to getting work where [she] can come home and see [her] husband", Corrie actor Alan Halsall, whom she married in 2009.
Wild at Heart airs Sunday, December 30 at 8pm on ITV1.