Highlight duplicates across two sheets or tables

I have two lists of ID's generated from First and Last Name and a Unique Identifier. Sheet 2 contains a list of known good data, Sheet 1 contains a list of data which may or may not be accurate. I want to automatically highlight in green (using formulas rather then VBA) any value that appears on both lists.

Note: I am only concerned about 1 column on each sheet (I'm also okay with placing them in tables on the same sheet)

How would I go about doing this? I tried placing the good data at the bottom of the column containing the unknown data and checking for duplicates, but that leaves to much room for error if a faulty ID appears multiple times within the unknown data and none in the 'good' data.

Thanks in advance!!

EDIT: And it be even awesomer if I could highlight the entire row....

you have excel 2012 so you should be able to conditional format based on whats on another sheet
http://www.techrepublic.com/blog/mso...eferences/3727

cant say without seeing an example

Of the data?
It is two columns of data on two worksheets that look something like this where col. C is where I want to check for matches on both sheets and highlight on the first sheet
___A_______B__________C__________________D____
1_Smith___John_____SmithJoh0000000001___0000000001

=countif(sheet2!$c:$c,$c1)

copy the format across the row as far as you need