Selina Scott has presented BBC Breakfast News and The Clothes Show
TV presenter Selina Scott is suing TV channel Five for age discrimination.
Scott was reportedly being lined up to provide maternity cover for Five News host Natasha Kaplinsky, but was subsequently overlooked.
A Tribunals Service spokeswoman confirmed that Scott, 57, was bringing a case against Five but said it was "at an early stage".
Scott's agent said the case was a matter for her lawyers. Five said it would "vigorously defend" itself.
"We do not accept this claim," a spokesman added.
Kaplinsky began her maternity leave a fortnight ago.
Five - whose bulletins are produced by Sky News - announced in June that the popular presenter would be replaced by Matt Barbet, 32, and Isla Traquair, 28.
Media reports have suggested that Scott will claim the channel went back on an agreement that she would cover for Kaplinsky.
Scott shot to fame as part of BBC's Breakfast Time programme in the early 1980s before presenting programmes including The Clothes Show.
She has also presented election coverage on Sky as well as hosting shows in the US.
Earlier this year, Scott complained about the lack of older female presenters on television.
"How many women are there on mainstream current affairs programmes who are over 50?" she said in January.
"Anna Ford has retired, Moira Stuart has been bumped off, yet you look around and see lots of men."