diff --git a/src/JOSPreDefinitions/BuiltInTypes.jl b/src/JOSPreDefinitions/BuiltInTypes.jl
index 9660962..b0f65dd 100644
--- a/src/JOSPreDefinitions/BuiltInTypes.jl
+++ b/src/JOSPreDefinitions/BuiltInTypes.jl
@@ -8,13 +8,17 @@ export _Exception, _TypeException, _IO,
 @defbuiltin _TypeException(Type{Exception})
 @defbuiltin _IO(IO)
 
+@defclass(_Int, [Top], [], metaclass=BuiltInClass)
+
 @defbuiltin _Int8(Int8)
 @defbuiltin _Int16(Int16)
-@defbuiltin _Int32(Int32)
-@defbuiltin _Int64(Int64)
 @defbuiltin _Int128(Int128)
 
-@defbuiltin _Int(Int)
+@defclass(_Int32, [_Int], [], metaclass=BuiltInClass)
+class_of(instance::Int32) = _Int32
+
+@defclass(_Int64, [_Int], [], metaclass=BuiltInClass)
+class_of(instance::Int64) = _Int64
 
 @defbuiltin _Bool(Bool)
 
diff --git a/test/test_built_in_classes.jl b/test/test_built_in_classes.jl
index dea0e43..98f6913 100644
--- a/test/test_built_in_classes.jl
+++ b/test/test_built_in_classes.jl
@@ -3,8 +3,8 @@ using Test
 
 @testset "Built-In Classes" begin
     @testset "Print object" begin
-        result = @capture_out show(class_of(1))
-        @test result == "<BuiltInClass _Int>"
+        result = @capture_out show(class_of(Int64(1)))
+        @test result == "<BuiltInClass _Int64>"
 
         result = @capture_out show(class_of("Foo"))
         @test result == "<BuiltInClass _String>"