diff --git a/dumux/material/fluidmatrixinteractions/2p/smoothedlinearlaw.hh b/dumux/material/fluidmatrixinteractions/2p/smoothedlinearlaw.hh
index 7cf2badd391a75cfb4b084ea906884d23531224b..6f33091c44a7156a5cab977ffa346c77c41d92c0 100644
--- a/dumux/material/fluidmatrixinteractions/2p/smoothedlinearlaw.hh
+++ b/dumux/material/fluidmatrixinteractions/2p/smoothedlinearlaw.hh
@@ -66,6 +66,12 @@ public:
     static constexpr bool isRegularized()
     { return false; }
 
+    /*!
+     * \brief Return the number of fluid phases
+     */
+    static constexpr int numFluidPhases()
+    { return 2; }
+
     /*!
      * \brief The parameter type
      * \tparam Scalar The scalar type