Professor Jason Leitch has urged Scots to wear a face covering during "Christmas celebrations" this year.
Professor Leitch made the statement when speaking to press at the Scottish Government's daily coronavirus briefing.
The Senior Clinical Advisor says the Scottish public should do so in accordance with guidance set out by the World Health Organisation (WHO).
Guidance from WHO published this week states that for households who chose to mix on these dates they should wear face coverings indoors, just as they would at a shop.
And responding to a question from the media, Professor Leitch confirmed he would support that advice.
He said: "The WHO advice is good. It came out because the WHO are worried about Christmas, of course, around the world, not just Scottish Christmas.
"And what they suggest is very sensible. It says, if you are indoors, with people who are not in your household, you should think about wearing a face covering.
"That's true in workplaces in Scotland just now. That should also be true when you have your Christmas celebration if you can possibly do it."
The new Christmas guidance from WHO reads: “Indoor gatherings, even smaller ones, can be especially risky because they bring together groups of people, young and old, from different households, who may not all be adhering to the same infection prevention measures.
“Gatherings should be held outside if possible, and participants should wear masks and maintain physical distancing. If held indoors, limiting group size and ensuring good ventilation to reduce exposure risk are key.
“It may feel awkward to wear masks and practise physical distancing when around friends and family, but doing so contributes significantly to ensuring that everyone remains safe and healthy.
“Vulnerable people and older friends or relatives may find it very difficult to ask loved ones to stay away physically, regardless of the anxieties or concerns they may have. Consider what others may be feeling and the difficult decisions they will be facing.”
