George Alagiah has spoken of his guilt at having to use disabled toilets while having no visible disability.
The BBC newsreader, who has stage four bowel cancer, used the facilities in the past because of having a stoma bag attached to his stomach.
When disabled people saw him using the toilets he would feel the need to "apologise and explain", he said.
Talking about living with the bag for the first time, Alagiah said it also required him to get his suits altered.
A stoma bag is an opening in the stomach where faeces are collected in a bag after part or all of the bowel is removed due to a disease or obstruction.
Alagiah, 63, returned to presenting duties in January this year after his bowel cancer returned in December 2017.
He no longer has a stoma bag after undergoing reversal treatment.
'Apologise and explain'
Speaking about living with a stoma on In Conversation With George Alagiah: A Bowel Cancer UK Podcast, he said: "I used to find it difficult. I had a stoma but I didn't look disabled, and I would be turning the key in a disabled loo in a motorway service station or something.
"And if there was a queue and somebody obviously disabled (was there), I used to feel guilty and feel like I needed to apologise and explain.
"The reason you need to go into a disabled loo is that you just need a little bit of space, to get the contents of your blue bag out and the sanitising equipment and so on."
The charity Crohn's & Colitis UK has launched a campaign calling for companies to install new signs on disabled toilets to explain that not all disabilities are visible.
It says people with such "invisible disabilities" are subjected to discrimination for using facilities they urgently need.
In 2017, Tottenham Hotspur became the first football club to feature such a slogan on their disabled toilets.
Alagiah also spoke of adjusting his clothes and changing his outfits to fit the bag, which included taking his suits out and wearing braces.
Speaking about his concerns over returning to work with the bag, he said: "I [was] always looking around at my colleagues and thinking, 'Can they smell anything, can they hear anything?"'
Dr Lisa Wilde, from Bowel Cancer UK, said stomas remained a "hidden part of living with the disease".
She said: "We know that many of our supporters face everyday challenges to manage their stoma, and one of these is accessing disabled toilets, as it's not a visible disability.
"We're determined to improve the quality of life of everyone affected by bowel cancer and to help people live well with a stoma."
Alagiah hosts the first series of Bowel Cancer UK's podcasts, interviewing supporters and leading experts on the disease, as well as discussing his own treatment and diagnosis.
Bowel cancer is the UK's fourth most common cancer and second biggest killer cancer with more than 16,000 people dying from the disease every year.
It is treatable and can be curable, especially if diagnosed early.