diff --git a/src/pair_born.h b/src/pair_born.h
index acfa3ccfc9..eaae688c38 100644
--- a/src/pair_born.h
+++ b/src/pair_born.h
@@ -40,6 +40,7 @@ class PairBorn : public Pair {
   void write_data(FILE *) override;
   void write_data_all(FILE *) override;
   double single(int, int, int, int, double, double, double, double &) override;
+  void born_matrix(int, int, int, int, double, double, double, double &, double &) override;
   void *extract(const char *, int &) override;
 
  protected: