diff --git a/graf3d/gl/src/TGLFontManager.cxx b/graf3d/gl/src/TGLFontManager.cxx
index 7142e7568489f..9fb05a1b0ca9e 100644
--- a/graf3d/gl/src/TGLFontManager.cxx
+++ b/graf3d/gl/src/TGLFontManager.cxx
@@ -276,7 +276,7 @@ void TGLFont::Render(const TString &txt) const
    }
 
    // FTGL is not const correct.
-   const_cast<FTFont*>(fFont)->Render(txt);
+   const_cast<FTFont*>(fFont)->Render(txt.Data());
 
    if (scaleDepth) {
       glPopMatrix();