diff --git a/http-mirage-client.opam b/http-mirage-client.opam
index 041591b..c5b0d50 100644
--- a/http-mirage-client.opam
+++ b/http-mirage-client.opam
@@ -22,6 +22,7 @@ depends: [
   "mirage-crypto-rng" {with-test}
   "mirage-time-unix" {with-test & >= "3.0.0"}
   "h2" {>= "0.10.0"}
+  "tls" {>= "1.0.0"}
 ]
 build: [
   ["dune" "subst"] {dev}
diff --git a/src/http_mirage_client.ml b/src/http_mirage_client.ml
index 1c55ae2..637f556 100644
--- a/src/http_mirage_client.ml
+++ b/src/http_mirage_client.ml
@@ -383,7 +383,8 @@ let single_request
 
 let tls_config ?tls_config ?config authenticator user's_authenticator =
   lazy
-    (match tls_config with
+    (let ( let* ) = Result.bind in
+     match tls_config with
     | Some cfg -> Ok (`Custom cfg)
     | None -> (
       let alpn_protocols =
@@ -391,12 +392,14 @@ let tls_config ?tls_config ?config authenticator user's_authenticator =
         | None -> ["h2"; "http/1.1"]
         | Some (`H2 _) -> ["h2"]
         | Some (`HTTP_1_1 _) -> ["http/1.1"] in
-      match authenticator, user's_authenticator with
-      | Ok authenticator, None ->
-        Ok (`Default (Tls.Config.client ~alpn_protocols ~authenticator ()))
-      | _, Some authenticator ->
-        Ok (`Default (Tls.Config.client ~alpn_protocols ~authenticator ()))
-      | (Error _ as err), None -> err))
+      let* authenticator =
+        match authenticator, user's_authenticator with
+        | Ok authenticator, None -> Ok authenticator
+        | _, Some authenticator -> Ok authenticator
+        | (Error _ as err), None -> err
+      in
+      let* cfg = Tls.Config.client ~alpn_protocols ~authenticator () in
+      Ok (`Default cfg)))
 
 let resolve_location ~uri ~location =
   match String.split_on_char '/' location with