Hello and thanks for using Just Answer.
I am Al and am happy to assist you with your enquiry.
It is usually preferable to have a separate Will in countries in which you own immoveable property even if your UK will is technically valid in that country.
The reason for this is that it often makes it easier in practice to transfer ownership of the property on death.
Under the law of England and Wales immoveable assets devolve in accordance with the law of the country in which they are situated.
Therefore you need to take advice from a Portuguese lawyer as to how the property would pass on death, whether a separate Portuguese will or a codicil to your existing will is preferable and whether Portuguese succession laws apply.
'Portuguese succession laws may well not apply to English nationals because Portuguese law may look to the nationality of the Deceased but this would need to be confirmed by a Portuguese lawyer.
A separate will need not revoke your existing will governed by the law of England and Wales.
A specific clause should be included in any Portuguese will making it clear that it only relates to property situated in Portugal and does not revoke your existing will.
As regards ***** ***** in America, again if you have property in the US, it is certainly advisable for you to make a Will with a US lawyer to avoid any problems.
I hope this assists.