How to prevent duplicates in 2 columns in one table

We know how to define column as unique, but what to do where you need to prevent duplicate in 2 columns?
This is a state:

CREATE TABLE #tmp
(
Id INT,
Wine VARCHAR(50),
Country VARCHAR(50)
)

INSERT INTO #tmp VALUES 
(1,'Merlot','France')
INSERT INTO #tmp VALUES
(2,'Merlot','Argentina')
INSERT INTO #tmp VALUES
(3,'Malbec','Argentina')

SELECT * FROM #tmp
DROP TABLE #tmp

A result is:

Id |  Wine    |  Country
----------- ------------------
1 |  Merlot   |  France
2 |  Merlot   |  Argentina
3 |  Malbec |  Argentina

A target to prevent:

Id |  Wine    |  Country
----------- ------------------

1 |  Merlot   |  France
2 |  Merlot   |  Argentina
3 |  Malbec |  Argentina

4 |  Merlot   |  France
5 |  Caberne   |  France

That means table allow duplicate Wines and duplicate Countries, but must prevent double rows.
A solution is to add next row after table creation:

ALTER TABLE  #tmp      ADD UNIQUE(Wine, Country)

Enjoy