Adding a non nullable column without a default

When trying to add a column with a default that is not nullable to an existing table you get an error message (even when there are no records in the table)

ALTER TABLE only allows columns to be added that can contain nulls or have a DEFAULT definition specified. Column 'NewColumn' cannot be added to table 'tbl_test' because it does not allow nulls and does not specify a DEFAULT definition.

There is however an easy workaround.

ALTER TABLE dbo.tbl_test
ADD NewColumn smalldatetime NOT NULL
CONSTRAINT DF_ToDrop DEFAULT ('2000-01-01')

ALTER TABLE dbo.tbl_test
DROP CONSTRAINT DF_ToDrop