When Matt Lucas updated a 20-year-old comedy song with lyrics giving advice about avoiding coronavirus, he expected about 500 people to watch it.
"That's probably as many people as would normally look at my Twitter," the Little Britain star says.
But the video for his revised Baked Potato Song has now had three million views, and he is about to release it to raise funds for his FeedNHS campaign.
"When the idea was put to me, it was a no brainer," he tells BBC News.
Lucas first duetted with a baked potato on madcap comedy quiz Shooting Stars, where the singing vegetable delivered some sensible life lessons - from "Do be early, don't be late" to "Always eat what's on your plate".
"Sometimes people write to me about that song because it appeared on Shooting Stars about 20 years ago, and it's something that people still remember," Lucas says.
He was inspired to revisit it after seeing footage of people socialising last Tuesday, when he was already in isolation.
"I was just trying to think of a way of helping to spread the message rather than the virus, and I thought, if I can connect with kids, then maybe the kids can tell their parents," he says.
"I was sat at my piano and I just remembered the baked potato song."
In its new incarnation, the baked potato instructs people to wash their hands, stay indoors and not touch their faces.
"I watched over the next 48 hours as it went viral, and three million people have viewed it on Twitter," says Lucas.
"And then people started doing their own versions and their own animations. And kids were filming themselves singing it and sending it to me, and it sort of took on a life of its own."
As that was happening, Lucas was speaking to actors Damian Lewis and Helen McCrory, as well as the boss of food chain Leon, to set up a campaign that would provide hot meals to NHS workers.
FeedNHS is aiming to take food from the thousands of cafes, restaurants and canteens that have been forced to shut down and send it to hospitals. A fundraising page has already raised almost £600,000.
"I have an aunt who's in hospital at the moment with the virus. I know two people who've passed away from it," Lucas explains.
"People message me on social media to say they work in the NHS and they're completely oversubscribed. So it was pretty plain and simple to all of us that we should try and get them at least one hot meal a day, and it's good quality food as well."
So a singing baked potato will be helping to feed doctors and nurses.
Lucas is about to become the new co-host of The Great British Bake Off and is rumoured to be working on new Little Britain material with David Walliams. But he says he's not using the time afforded by isolation to work on comedy scripts.
"The only creative thing I've done in the last two and a half weeks is rewrite the lyrics to this song," he says.
"I've only been focused on this charity, my family and my friends.
"I want to be able to look back and think that I tried to do something to help some people during this particular crisis. I have asthma so I have to isolate. But many people are literally risking their lives to help people."