ITV will refund "misled" viewers who used paid voting in the Britain's Got Talent final to vote for the winning act, or donate their money to charity.
This follows a ruling by broadcasting watchdog, Ofcom, which determined "ITV broke broadcasting rules by misleading viewers during the series finale".
Following the show's finale earlier this year, a total of 1,175 complaints poured in about the winning act, Jules O'Dwyer and her dog Matisse.
Viewers were outraged after it emerged, on the morning after the final, that Matisse had not performed the tightrope stunt, the most spectacular element of the winning sketch.
It starred O'Dwyer as a policewoman going after "sausage thief" Matisse and another of her pets, three-legged Skippy.
In a statement, Ofcom said: "We accepted ITV had no intention to deceive the audience. However, the presentation of the act did not make clear to viewers that a central part was performed by a second dog.
"Broadcasters inviting viewers to vote using premium rate numbers have a particular responsibility to ensure the audience is clear about what they are voting for.
"By failing to do so, we've concluded the presentation of the act was likely to have materially misled some people."
ITV said in an official statement: "The Britain's Got Talent production team apologised at the time for not making it clearer to the judges and viewers at home that three dogs were involved in the final performance.
"There was never any intention to mislead viewers and in their decision Ofcom said they 'have no reason to believe that there was any intention to deceive viewers that the tightrope walk actually involved a second dog'."
Following this, it went on to say: "The majority of votes cast for Jules' act were received through the free voting app.
"However, we accept that some viewers who voted for the winning act by a paid voting route may wish to seek a refund, or that the cost of their vote be donated in full to the Royal Variety charity.
"Details about how to obtain a refund, or to request that a refund be donated to the charity, are now on our website."
ITV will only refund people who voted for the winning act.
A message on the ITV website, regarding the refund, said: "For avoidance of doubt, viewers who voted by a paid route for any other act in the final of BGT 2015 (ie other than the winning act) are not eligible for a refund or to request donation of a refund."
More than 13 million viewers watched O'Dwyer and Matisse become the second dog act to win Britain's Got Talent - following Ashleigh Butler and Pudsey in 2012 - in the highest-rated final since that year.
Voting figures showed that they won by just 2% - getting 22.6% of votes compared with 20.4% for magician Raven.