diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/BaseXSSFFormulaEvaluator.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/BaseXSSFFormulaEvaluator.java
index 0e41e50cb..bbad20e51 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/BaseXSSFFormulaEvaluator.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/BaseXSSFFormulaEvaluator.java
@@ -73,9 +73,14 @@ public abstract class BaseXSSFFormulaEvaluator extends BaseFormulaEvaluator {
     }
     
     protected void setCellType(Cell cell, CellType cellType) {
-        EvaluationWorkbook evaluationWorkbook = getEvaluationWorkbook();
-        BaseXSSFEvaluationWorkbook xewb = BaseXSSFEvaluationWorkbook.class.isAssignableFrom(evaluationWorkbook.getClass()) ? (BaseXSSFEvaluationWorkbook) evaluationWorkbook : null;
-        
-        ((XSSFCell) cell).setCellType(cellType, xewb);
+        if (cell instanceof  XSSFCell) {
+            EvaluationWorkbook evaluationWorkbook = getEvaluationWorkbook();
+            BaseXSSFEvaluationWorkbook xewb = BaseXSSFEvaluationWorkbook.class.isAssignableFrom(evaluationWorkbook.getClass()) ? (BaseXSSFEvaluationWorkbook) evaluationWorkbook : null;
+
+            ((XSSFCell) cell).setCellType(cellType, xewb);
+        } else {
+            // could be an SXSSFCell
+            cell.setCellType(cellType);
+        }
     }
 }