DataTable with html formating

Hi,

I have a SPGridView in my webpart and it is bounded to a DataTable. I would like to add a sub-table in one of the columns (fieldc), when I tried the following, it doesn't recognize the html tag. How can I do it so that it will recognize the html tag?

DataTable dt = new DataTable();
DataRow row = dt.NewRow();

row["field1"] ="aaa"; 
row["fieldb"] ="bbb"; 
row["fieldc"] ="<table><tr><td>ccc</td></tr></table>";  <---

Thanks in advance. Your help would be greatly appreciated!