TV reality shows Strictly Come Dancing and X Factor are going head to head in a battle for ratings at weekends.
The two shows will start at the same time and overlap for 65 minutes when the first show of the new series of Strictly starts on 19 September.
ITV are said to be disappointed by what they described as the BBC's "aggressively competitive scheduling".
But the BBC said Strictly's slightly later start time was because a new series of Merlin is also starting.
The two shows have slightly overlapped in the past, although Strictly usually finished before X Factor allowing fans to watch both if they wanted to.
Now fans will have to make a choice, and ITV's not happy about it.
An ITV source is reported as saying: "Given that millions of people enjoy watching both shows, such aggressively competitive scheduling is neither in the interests of the licence fee-paying public, nor viewers generally."
But a BBC spokeswoman said the two shows had co-existed for many years.
"This year is no different," they said. "Indeed there is even more choice for viewers with Strictly launching on a Friday and ITV scheduling its results show on a Sunday."