diff --git a/src/templates/docx-postprocess.ts b/src/templates/docx-postprocess.ts
index 6273311..c590045 100644
--- a/src/templates/docx-postprocess.ts
+++ b/src/templates/docx-postprocess.ts
@@ -387,13 +387,22 @@ function addWatermarkToHeaderXml(headerXml: string, text: string): string {
   let nextXml = ensureWordNamespace(headerXml, 'w:hdr');
   nextXml = ensureNamespace(nextXml, 'w:hdr', 'xmlns:v', 'urn:schemas-microsoft-com:vml');
   nextXml = ensureNamespace(nextXml, 'w:hdr', 'xmlns:o', 'urn:schemas-microsoft-com:office:office');
+  nextXml = ensureNamespace(nextXml, 'w:hdr', 'xmlns:w10', 'urn:schemas-microsoft-com:office:word');
 
   return nextXml.replace('</w:hdr>', `${watermarkParagraphXml(text)}</w:hdr>`);
 }
 
 function watermarkParagraphXml(text: string): string {
   const escapedText = escapeXmlAttribute(text);
-  return `<w:p><w:r><w:pict><v:shape id="DocgenWatermark" o:spid="_x0000_s1025" type="#_x0000_t136" style="position:absolute;margin-left:0;margin-top:0;width:468pt;height:117pt;rotation:315;z-index:-251654144" fillcolor="silver" stroked="f"><v:fill opacity=".35"/><v:textpath style="font-family:Calibri;font-size:1pt" string="${escapedText}"/></v:shape></w:pict></w:r></w:p>`;
+  return `<w:p><w:r><w:pict>${watermarkShapeTypeXml()}${watermarkShapeXml(escapedText)}</w:pict></w:r></w:p>`;
+}
+
+function watermarkShapeTypeXml(): string {
+  return '<v:shapetype id="_x0000_t136" coordsize="21600,21600" o:spt="136" adj="10800" path="m@7,l@8,m@5,21600l@6,21600e"><v:formulas><v:f eqn="sum #0 0 10800"/><v:f eqn="prod #0 2 1"/><v:f eqn="sum 21600 0 @1"/><v:f eqn="sum 0 0 @2"/><v:f eqn="sum 21600 0 @3"/><v:f eqn="if @0 @3 0"/><v:f eqn="if @0 21600 @1"/><v:f eqn="if @0 0 @2"/><v:f eqn="if @0 @4 21600"/><v:f eqn="mid @5 @6"/><v:f eqn="mid @8 @5"/><v:f eqn="mid @7 @8"/><v:f eqn="mid @6 @7"/><v:f eqn="sum @6 0 @5"/></v:formulas><v:path textpathok="t" o:connecttype="custom" o:connectlocs="@9,0;@10,10800;@11,21600;@12,10800" o:connectangles="270,180,90,0"/><v:textpath on="t" fitshape="t"/><v:handles><v:h position="#0,bottomRight" xrange="6629,14971"/></v:handles><o:lock v:ext="edit" text="t" shapetype="t"/></v:shapetype>';
+}
+
+function watermarkShapeXml(escapedText: string): string {
+  return `<v:shape id="DocgenWatermark" o:spid="_x0000_s1025" type="#_x0000_t136" style="position:absolute;margin-left:0;margin-top:0;width:527.85pt;height:131.95pt;rotation:315;z-index:251659264;mso-position-horizontal:center;mso-position-horizontal-relative:margin;mso-position-vertical:center;mso-position-vertical-relative:margin;mso-wrap-edited:f" fillcolor="#C0C0C0" stroked="f"><v:fill opacity=".22"/><v:textpath style="font-family:&quot;Calibri&quot;;font-size:1pt" string="${escapedText}"/><w10:wrap anchorx="margin" anchory="margin"/></v:shape>`;
 }
 
 async function ensureContentTypeOverride(
diff --git a/test/templates/docx-postprocess.test.ts b/test/templates/docx-postprocess.test.ts
index 46fd65e..7f1ad58 100644
--- a/test/templates/docx-postprocess.test.ts
+++ b/test/templates/docx-postprocess.test.ts
@@ -70,6 +70,10 @@ describe('DOCX template post-processing', () => {
     expect(documentXml).toContain('<w:headerReference w:type="default" r:id="');
     expect(headerXml).toContain('<v:shape');
     expect(headerXml).toContain('DocgenWatermark');
+    expect(headerXml).toContain('<v:shapetype id="_x0000_t136"');
+    expect(headerXml).toContain('mso-position-horizontal:center');
+    expect(headerXml).toContain('mso-position-vertical:center');
+    expect(headerXml).toContain('<w10:wrap anchorx="margin" anchory="margin"/>');
     expect(headerXml).toContain('string="DRAFT"');
   });