diff --git a/src/libslic3r/GCode/Thumbnails.hpp b/src/libslic3r/GCode/Thumbnails.hpp
index fe7ab69c5..30bb6b653 100644
--- a/src/libslic3r/GCode/Thumbnails.hpp
+++ b/src/libslic3r/GCode/Thumbnails.hpp
@@ -9,6 +9,8 @@
 #include <memory>
 #include <string_view>
 
+#include <boost/beast/core/detail/base64.hpp>
+
 namespace Slic3r::GCodeThumbnails {
 
 struct CompressedImageBuffer