diff --git a/common/font/outline_font.cpp b/common/font/outline_font.cpp
index 638baab88a..497495ed38 100644
--- a/common/font/outline_font.cpp
+++ b/common/font/outline_font.cpp
@@ -334,9 +334,19 @@ VECTOR2I OUTLINE_FONT::getTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_pt
                                         bool aMirror, const VECTOR2I& aOrigin,
                                         TEXT_STYLE_FLAGS aTextStyle ) const
 {
-    VECTOR2D glyphSize = aSize;
-    
     std::lock_guard<std::mutex> guard( m_freeTypeMutex );
+
+    return getTextAsGlyphsUnlocked( aBBox, aGlyphs, aText, aSize, aPosition, aAngle, aMirror,
+            aOrigin, aTextStyle );
+}
+
+VECTOR2I OUTLINE_FONT::getTextAsGlyphsUnlocked( BOX2I* aBBox, std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
+        const wxString& aText, const VECTOR2I& aSize,
+        const VECTOR2I& aPosition, const EDA_ANGLE& aAngle,
+        bool aMirror, const VECTOR2I& aOrigin,
+        TEXT_STYLE_FLAGS aTextStyle ) const
+{
+    VECTOR2D glyphSize = aSize;
     FT_Face  face = m_face;
     double   scaler = faceSize();
 
@@ -478,7 +488,7 @@ VECTOR2I OUTLINE_FONT::getTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_pt
     {
         std::vector<std::unique_ptr<GLYPH>> underscoreGlyphs;
 
-        getTextAsGlyphs( nullptr, &underscoreGlyphs, wxT( "_" ), aSize, { 0, 0 }, ANGLE_0, false,
+        getTextAsGlyphsUnlocked( nullptr, &underscoreGlyphs, wxT( "_" ), aSize, { 0, 0 }, ANGLE_0, false,
                          { 0, 0 }, aTextStyle & ~TEXT_STYLE::OVERBAR );
 
         OUTLINE_GLYPH* underscoreGlyph = static_cast<OUTLINE_GLYPH*>( underscoreGlyphs[0].get() );
diff --git a/include/font/outline_font.h b/include/font/outline_font.h
index 0ccf703920..d04ce98d28 100644
--- a/include/font/outline_font.h
+++ b/include/font/outline_font.h
@@ -135,6 +135,12 @@ protected:
                               const VECTOR2I& aPosition, const EDA_ANGLE& aAngle, bool aMirror,
                               const VECTOR2I& aOrigin, TEXT_STYLE_FLAGS aTextStyle ) const;
 
+private:
+    VECTOR2I getTextAsGlyphsUnlocked( BOX2I* aBoundingBox, std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
+                              const wxString& aText, const VECTOR2I& aSize,
+                              const VECTOR2I& aPosition, const EDA_ANGLE& aAngle, bool aMirror,
+                              const VECTOR2I& aOrigin, TEXT_STYLE_FLAGS aTextStyle ) const;
+
 private:
     // FreeType variables