I live in Italy and have for years, but I have accepted to work several months on a project in the US (I will return to italy where I still live) I am not sure what address to put on the w4. Can I put my foreign address on the W4, technically speaking, I am not resident in any US state, i.e can I pay federal but not state taxes?

Thanks.

Out your U.S. address on the W-4. It does NOT get submitted to the IRS, but rather is filed in payroll.