British former Tour de France cyclist Robert Millar has completed a transition to become a woman.
The 58-year-old has decided to go public with the gender change because she says there is "a much better acceptance and understanding".
Millar was best known for winning the King of the Mountains prize in the Tour de France in 1984.
Philippa York, who becomes the first high-profile cyclist to go public, made the statement on cyclingnews.com.
York, who says she has been going through the transition since 2000, added: "The outcome of that journey has meant that for a considerable time now I have lived as Philippa.
"The steps taken over a prolonged period under the watchful eye of the medical profession to complete the transition from one gender to another can be difficult and are always only taken after much soul searching and anguish."
The Scot is part of ITV4's commentary team, alongside fellow former cycling professionals Chris Boardman and David Millar, for the Tour de France, which runs until 23 July.
"As much as I've guarded my privacy over the years there are a few, I believe obvious, reasons to why I haven't had a public "image" since I transitioned.
"Gratifyingly, times have moved on from ten years ago when my family, friends and I were subjected to the archaic views and prejudice that some people and certain sections of the tabloid media held."
- Robert Millar: the King of the Mountains
In 1984 Millar was the second Briton to win a Tour stage, and his fourth-placed Tour finish in that year was a record for a British rider.
Millar also came second in the 1985 and 1986 Tours of Spain, as well as runner-up in the 1987 Giro d'Italia. He won three mountain stages in the Tour, all in the Pyrenees.
What happened after Millar's cycling success?
- Millar retired in 1995 and was then appointed British national road coach
- He went on to write for several cycling magazines
- Reports first emerged in 2000 claiming a gender change, but there was no confirmation from Millar
- In 2002, Millar appeared in Manchester with the Scotland team in the Commonwealth Games
- Since then public appearances have been rare
"While there has been some speculation concerning my gender over the past decade, perhaps it'll now be better understood why unwelcome and unasked for intrusions into that transition have been damaging not only to myself but to those I love," York said.
"Thankfully the people in my family who I cherish have since matured and grown into strong and independent individuals, therefore the need to protect them has lessened.
"This, combined with their support, encouragement and the shift in modern society's attitudes, means that this will be a step forward for everyone."
"As much as various articles and blogs have been published using my former identity of Robert, well that was then and this is now. I'd like to take this opportunity to thank the different organisations and those 'in the know' for guarding my privacy as long as they have."