Dr Sarah Jarvis has sent out a warning ahead of the new face mask rules for shops, which come into play this week.
As of Friday, July 24, face coverings will be compulsory in shops and on public transport in England, in a bid to prevent coronavirus from spreading.
Those who do not comply with the new rule could face a fine.
The new Good Morning Britain doc - who is standing in for Hilary Jones while he is on holiday - told viewers that wearing the mask alone will not help to keep coronavirus at bay.
She explained that they have to be used effectively to make sure that they do not get contaminated, and suggested that people get used to wearing them at home.
Dr Sarah also warned that if we do not keep up with washing our hands regularly, we risk contaminating our mask - and our face.
She said: "One of the big issues with face masks is that if you fiddle with them and you haven't washed your hands then you could contaminate your face.
"It's a really good idea to start wearing one when you are at home.
"That will mean you can get into the habit of putting it on only using the straps, not touching your face when taking it on or off.
"Not putting it underneath your chin or dangling it on one ear - none of those things will work and could contaminate you.
"And not putting it under your nose."
Good Morning Britain airs weekdays at 6am on ITV.
