Is it possible to get DISTINCT rows from RETURNING clause?

Hi,

Is it possible to get DISTINCT rows from an UPDATE statement using RETURNING
clause?

"MYTABLE" columns are:APRIMARYKEYCOLUMNABOOLEANCOLUMNEMAILCOLUMN1COLUMN2COLUMN3

UPDATE using RETURNING clause query:
UPDATE MYTABLE SET ABOOLEANCOLUMN = true FROM MYTEMPTABLE WHERE EMAIL =
MYTEMPTABLE.EMAIL RETURNING EMAIL, COLUMN1, COLUMN2, COLUMN3;

Here in this case, I expect to return distinct rows from these columns:
EMAIL, COLUMN1, COLUMN2, COLUMN3. 

I even tried out some ways of getting distinct rows, but it doesn't work.
Though I can still solve this at application layer, I'm trying to find
whether this could be controlled at query-level.  Any different
ideas/suggestions are appreciated.

Regards,
Gnanam