diff --git a/storm/Big.cpp b/storm/Big.cpp
index ab80a40..9169fc1 100644
--- a/storm/Big.cpp
+++ b/storm/Big.cpp
@@ -1,4 +1,5 @@
 #include "storm/Big.hpp"
+#include "storm/big/BigData.hpp"
 #include "storm/big/Ops.hpp"
 #include "storm/Memory.hpp"
 #include <cstring>
diff --git a/storm/Big.hpp b/storm/Big.hpp
index c9646e2..c056078 100644
--- a/storm/Big.hpp
+++ b/storm/Big.hpp
@@ -1,9 +1,10 @@
 #ifndef STORM_BIG_HPP
 #define STORM_BIG_HPP
 
-#include "storm/big/BigData.hpp"
 #include "Core.hpp"
 
+class BigData;
+
 void STORMAPI SBigAdd(BigData* a, BigData* b, BigData* c);
 
 void STORMAPI SBigAnd(BigData* a, BigData* b, BigData* c);
diff --git a/test/big/Internal.cpp b/test/big/Internal.cpp
index fe148a0..b680962 100644
--- a/test/big/Internal.cpp
+++ b/test/big/Internal.cpp
@@ -1,5 +1,6 @@
 // These are the original SBig tests which rely on internals
 #include "test/BigTest.hpp"
+#include "storm/big/BigData.hpp"
 #include <string>
 
 TEST_CASE("SBigAdd internal", "[big]") {
diff --git a/test/big/Ops.cpp b/test/big/Ops.cpp
index 5a6a29c..15f6147 100644
--- a/test/big/Ops.cpp
+++ b/test/big/Ops.cpp
@@ -1,4 +1,5 @@
 #include "test/BigTest.hpp"
+#include "storm/big/BigData.hpp"
 #include "storm/big/Ops.hpp"
 #include <vector>