Richard Madeley and Judy Finnigan have won a battle over the payment of income tax that could have big implications for other TV stars.
Richard Madeley and Judy Finnigan won after showing This Morning clips
They won the right to offset their agent's fees against income tax because they are "theatrical performers".
The loophole in the tax laws applies only to "actors, singers, musicians, dancers or theatrical artists".
They convinced a hearing they qualified with a clip of ex-This Morning host Madeley impersonating Ali G.
Madeley also provided other clips, including one of himself playing air guitar and pretending to sing in a rock band, and another in which he and Finnigan swap clothes.
But Special Commissioner Howard Nowlan said the Ali G sketch was "particularly good" and "very funny".
He ruled: "I accept without hesitation that Richard and Judy are entertainers and they are performers.
"If an artist is performing on television, in a club or even in the street and the performance can be described as `theatrical', the fact that the performer may never have set foot in a theatre is irrelevant."
Anne Robinson puts on a "performance"
The Inland Revenue denied it was a test case.
"We are currently considering the judgment before deciding whether to appeal
against it or to accept the decision of the Special Commissioner," a spokesman said.
The tax bill was for a six-year period while the married couple, now working for Channel 4, were with ITV's This Morning programme.
In a statement, Madeley and Finnigan said: "We are happy with the outcome. We were not asking for a change in the regulations. We always believed we were covered by existing law."
However, Mr Nowlan warned that not all big name TV presenters would be able to put forward the same argument as the couple.
He said stars such as Ant and Dec, Bruce Forsyth and Anne Robinson can all be classed as "theatrical artists".
But Newsnight's Jeremy Paxman, John Humphrys on Mastermind, newsreaders and weather forecasters do not meet the criteria.
"The common thread to Bruce Forsyth, Ant and Dec and Anne Robinson is that they are all putting on one or another form of act," Mr Nowlan said.
"Everything is a performance. And to my mind Richard and Judy share that attribute."