diff --git a/packages/nbdime/src/diff/widget/cell.ts b/packages/nbdime/src/diff/widget/cell.ts
index a0ad66f0..7f8c970f 100644
--- a/packages/nbdime/src/diff/widget/cell.ts
+++ b/packages/nbdime/src/diff/widget/cell.ts
@@ -126,7 +126,7 @@ export class CellDiffWidget extends Panel {
           header.addWidget(w);
         }
         if (model.cellId && id !== null) {
-          let w = createWidget(id);
+          let w = createWidget(`Cell ID: ${id}`);
           w.addClass(CELL_ID_CLASS);
           FlexPanel.setGrow(w, 1);
           header.addWidget(w);