How to specify encoding in .NET Interop.Excel.Workbooks.OpenText

I'm not able to find any information about the possibility of specifying encoding (utf-8 in particular) when opening a text file with the excel.Workbooks.OpenText method. My problem is that I'm trying to open a CSV file that is encoded in UTF-8 and without this setting it loads as a bunch of squiggles.

Thanks a lot!