diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h
index ce94af8..7784252 100644
--- a/include/mbedtls/ecdsa.h
+++ b/include/mbedtls/ecdsa.h
@@ -91,6 +91,9 @@
 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
     mbedtls_ecdsa_restart_det_ctx *det; /*!<  ecdsa_sign_det() sub-context  */
 #endif
+#if defined(MBEDTLS_PK_C)
+    mbedtls_ecdsa_context *ecdsa;       /*!<  used by the PK layer          */
+#endif
 } mbedtls_ecdsa_restart_ctx;
 
 #else /* MBEDTLS_ECP_RESTARTABLE */