Specify styling (font, in particular) for a certain cell in Prawn

Specify styling (font, in particular) for a certain cell in Prawn

I want to specify a font style for a certain cell. What I found in the
documentation is the capacity to do it for all the cell, but not for one I
need:
table data, :cell_style => { :font => "Times-Roman", :font_style => :italic }
How do I do that for only one cell?