Good Morning Britain's Dr Hilary Jones warned that although we might be allowed an international summer holiday, we need to be careful of foreign COVID variants.
The ban on foreign holidays is expected to be lifted for people in England from May 17 as part of the next easing of coronavirus restrictions.
The UK government's "green list" of countries to which people can travel without having to isolate for 14 days on their return is expected to be released this week, although it is understood details are still being finalised.
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Reports suggested the list could include about a dozen countries, although some newspapers suggested it could be fewer than 10.
Both The Times and The Guardian said destinations likely to make it onto the list for travel from May 17 include Portugal, Malta and Gibraltar, while the Telegraph said Spain, Greece and France could be added by the end of June.
But Mr Johnson has cautioned that while there will be "some openings up" from that date, the approach must be "sensible" to avoid an "influx of disease" when international travel resumes.
Speaking about the news Brits could jet off to European hotspots, the GMB doctor said he didn't want to be 'a killjoy' however, he is conflicted about foreign holidays this summer.
He said: "I understand people have been feeling very trapped and isolated and couped up and imprisoned - I understand that.
"But now people want to get out and about, it's good for peoples mental health.
"But I think to throw caution to the wind now would be a big mistake because we don't want another lockdown."
