Dr Hilary Jones warned Good Morning Britain viewers that the UK needs to "get a grip" and follow social distancing rules, to avoid a second wave of coronavirus.
As GMB hosts Piers Morgan and Susanna Reid covered the fact hospitals were apparently preparing for a "deadly" second wave soon, Dr Hilary urged people to help prevent the spread of Covid-19 before it is too late.
Hilary advised viewers on the "worrying" rise in cases in the UK, as well as specifically in care homes following the devastating scandal surrounding care home deaths from the virus earlier this year.
Now, as parts of the UK bring in a new rule limiting gatherings to just six people, the doctor told those watching to take the virus seriously.
Amid fears people are not following the social distancing guidelines anymore, as Piers suggested another national lockdown could be the result if they did not act fast, Hilary explained why people should listen now - and help to stop hospitals becoming too full again.
Referencing how other countries including France have seen a spike in new cases, Hilary warned we may not be far behind.
Speaking on the show on Monday, he said: "We've seen a rise in cases, over 3,000 again three days on the trot.
"We're seeing an increase in hospitalisations, there's nine deaths throughout the UK. That may not sound much now, but when you see a rise in cases inevitably you will see more hospitalisations.
"We're also seeing a rise in the number of cases in care homes, which is really worrying.
"These are the people who are most vulnerable, and there's been about 1,000 cases in care homes around the country.
"We need to get a grip on this, and make sure people do understand why social distancing is so important and that the rule of six is easy to understand.
"The number six is based on modeling rather than any science, but the more people individuals come into contact with, the more transmission will spread."
The new rules come into place on Monday across England, Scotland and Wales.
Good Morning Britain airs weekdays at 6am on ITV.
