how to format a cell while selecting..

Dear all

Hope all is well

I am not sure this is possible or not hence writing here.

In excel when selecting a cell the cell automatically should be formatted (font color= green,background= yellow). But when selecting any other cell then the previous selected cell has to be in default format and the current selected cell should be formatted (font color= green,background= yellow).

Kindly let me know if  this is possible.

Regards.

M.Raghavan