diff --git a/ethutil/rlp.go b/ethutil/rlp.go
index 69f80a0a6..195ef0efb 100644
--- a/ethutil/rlp.go
+++ b/ethutil/rlp.go
@@ -11,6 +11,7 @@ import (
 
 type RlpEncodable interface {
 	RlpEncode() []byte
+	RlpValue() []interface{}
 }
 
 type RlpEncoder struct {