string was not recognized as a valid datetime

Question

Hai guys

   when i am trying to fetch the data from gridview to textboxes by using the following code iam getting an error like"string was not recognized as a valid datetime"

DtpExpence.Value = Convert.ToDateTime(dgvCompanyExpences.SelectedRows[0].Cells[2].Value.ToString());


Please Help Anyone,Thanks in advance

Its very urgent..