diff --git a/spew/dump_test.go b/spew/dump_test.go
index 0d282c2..abe0a28 100644
--- a/spew/dump_test.go
+++ b/spew/dump_test.go
@@ -31,6 +31,7 @@ base test element are also tested to ensure proper indirection across all types.
 - Slice containing interfaces
 - Standard string
 - Nil interface
+- Sub-interface
 - Map with string keys and int vals
 - Map with custom formatter type on pointer receiver only keys and vals
 - Map with interface keys and values
@@ -402,7 +403,7 @@ func addStringDumpTests() {
 	addDumpTest(nv, "(*"+vt+")(<nil>)\n")
 }
 
-func addNilInterfaceDumpTests() {
+func addInterfaceDumpTests() {
 	// Nil interface.
 	var v interface{}
 	nv := (*interface{})(nil)
@@ -415,6 +416,17 @@ func addNilInterfaceDumpTests() {
 	addDumpTest(pv, "(*"+vt+")("+vAddr+")("+vs+")\n")
 	addDumpTest(&pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")("+vs+")\n")
 	addDumpTest(nv, "(*"+vt+")(<nil>)\n")
+
+	// Sub-interface.
+	v2 := interface{}(uint16(65535))
+	pv2 := &v2
+	v2Addr := fmt.Sprintf("%p", pv2)
+	pv2Addr := fmt.Sprintf("%p", &pv2)
+	v2t := "uint16"
+	v2s := "65535"
+	addDumpTest(v2, "("+v2t+") "+v2s+"\n")
+	addDumpTest(pv2, "(*"+v2t+")("+v2Addr+")("+v2s+")\n")
+	addDumpTest(&pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")("+v2s+")\n")
 }
 
 func addMapDumpTests() {
@@ -760,7 +772,7 @@ func TestDump(t *testing.T) {
 	addArrayDumpTests()
 	addSliceDumpTests()
 	addStringDumpTests()
-	addNilInterfaceDumpTests()
+	addInterfaceDumpTests()
 	addMapDumpTests()
 	addStructDumpTests()
 	addUintptrDumpTests()
diff --git a/spew/format_test.go b/spew/format_test.go
index cbc3bd7..d5b43b5 100644
--- a/spew/format_test.go
+++ b/spew/format_test.go
@@ -31,6 +31,7 @@ base test element are also tested to ensure proper indirection across all types.
 - Slice containing interfaces
 - Standard string
 - Nil interface
+- Sub-interface
 - Map with string keys and int vals
 - Map with custom formatter type on pointer receiver only keys and vals
 - Map with interface keys and values
@@ -681,7 +682,7 @@ func addStringFormatterTests() {
 	addFormatterTest("%#+v", nv, "(*"+vt+")"+"<nil>")
 }
 
-func addNilInterfaceFormatterTests() {
+func addInterfaceFormatterTests() {
 	// Nil interface.
 	var v interface{}
 	nv := (*interface{})(nil)
@@ -706,6 +707,26 @@ func addNilInterfaceFormatterTests() {
 	addFormatterTest("%#+v", pv, "(*"+vt+")("+vAddr+")"+vs)
 	addFormatterTest("%#+v", &pv, "(**"+vt+")("+pvAddr+"->"+vAddr+")"+vs)
 	addFormatterTest("%#+v", nv, "(*"+vt+")"+"<nil>")
+
+	// Sub-interface.
+	v2 := interface{}(uint16(65535))
+	pv2 := &v2
+	v2Addr := fmt.Sprintf("%p", pv2)
+	pv2Addr := fmt.Sprintf("%p", &pv2)
+	v2t := "uint16"
+	v2s := "65535"
+	addFormatterTest("%v", v2, v2s)
+	addFormatterTest("%v", pv2, "<*>"+v2s)
+	addFormatterTest("%v", &pv2, "<**>"+v2s)
+	addFormatterTest("%+v", v2, v2s)
+	addFormatterTest("%+v", pv2, "<*>("+v2Addr+")"+v2s)
+	addFormatterTest("%+v", &pv2, "<**>("+pv2Addr+"->"+v2Addr+")"+v2s)
+	addFormatterTest("%#v", v2, "("+v2t+")"+v2s)
+	addFormatterTest("%#v", pv2, "(*"+v2t+")"+v2s)
+	addFormatterTest("%#v", &pv2, "(**"+v2t+")"+v2s)
+	addFormatterTest("%#+v", v2, "("+v2t+")"+v2s)
+	addFormatterTest("%#+v", pv2, "(*"+v2t+")("+v2Addr+")"+v2s)
+	addFormatterTest("%#+v", &pv2, "(**"+v2t+")("+pv2Addr+"->"+v2Addr+")"+v2s)
 }
 
 func addMapFormatterTests() {
@@ -1335,7 +1356,7 @@ func TestFormatter(t *testing.T) {
 	addArrayFormatterTests()
 	addSliceFormatterTests()
 	addStringFormatterTests()
-	addNilInterfaceFormatterTests()
+	addInterfaceFormatterTests()
 	addMapFormatterTests()
 	addStructFormatterTests()
 	addUintptrFormatterTests()