Presenter Sian Lloyd has spoken for the first time about her experience of being stalked.
In an interview with Welsh current affairs programme Y Byd ar Bedwar, Maesteg-born Sian said the "intrusion" has changed her as a person.
Sian said she has often experienced unwanted attention during her long career as a weather presenter and TV personality.
But a particularly frightening incident at her mid-Wales home last year left her "looking over her shoulder".
The stalker had been present at a rally event where Sian had been giving out awards.
After returning home, Sian was shocked to find an envelope waiting for her, which contained an intimate picture.
"There was an accompanying letter that said: ‘This is for you and there’s plenty more where that came from’ - and he even gave his phone number,” she said.
Despite having the phone number, police were unable to trace the culprit.
Sian said the incident has left her paranoid and constantly suspicious when out and about.
“Sadly, I think it’s completely changed my life,” the 58-year-old said.
“I’ve gone from someone hyper-confident, carefree, going from one thing to another, never looking over my shoulder. Now I look over my shoulder, mentally and physically.
“I resent his intrusion enormously. You could say he’s done me a favour, as I’m incredibly alert because of what could go wrong, and it might sound as if I’m a scaredy-cat or paranoid but better that than the possibility of a tragic outcome.”
It is four years since wide-ranging laws against stalking were introduced in Wales and England.
Over the past year (2015/16) more than 1,000 prosecution proceedings have opened for alleged stalking in Wales and England, compared with 12,000 for the offence of harassment.
A survey by YouGov in April suggested the risk of being stalked online is increasing across the UK.
The most common form of stalking is by partners or ex-partners when a relationship ends.
But in ten per cent of cases - as with Sian Lloyd's experience - the stalker has no previous connection to the victim.
To see the full interview, watch y Byd ar Bedwar on Tuesday at 9.30pm on S4C.