diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java b/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
index 3442b0cea93..2e1510a65ee 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
@@ -18,6 +18,7 @@ package org.jetbrains.jet.codegen;
 
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
+import com.google.protobuf.ExtensionRegistry;
 import com.intellij.openapi.progress.ProcessCanceledException;
 import com.intellij.openapi.util.Pair;
 import com.intellij.psi.PsiElement;
@@ -42,6 +43,7 @@ import org.jetbrains.jet.descriptors.serialization.DescriptorSerializer;
 import org.jetbrains.jet.descriptors.serialization.ProtoBuf;
 import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.descriptors.impl.MutableClassDescriptor;
+import org.jetbrains.jet.lang.diagnostics.DiagnosticUtils;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.BindingContextUtils;
@@ -53,6 +55,7 @@ import org.jetbrains.jet.lang.resolve.constants.CompileTimeConstant;
 import org.jetbrains.jet.lang.resolve.java.AsmTypeConstants;
 import org.jetbrains.jet.lang.resolve.java.JvmAbi;
 import org.jetbrains.jet.lang.resolve.java.JvmAnnotationNames;
+import org.jetbrains.jet.lang.resolve.name.FqNameUnsafe;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.types.*;
 import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
@@ -349,25 +352,40 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
         }
         sw.writeSuperclassEnd();
 
-        LinkedHashSet<String> superInterfaces = new LinkedHashSet<String>();
-        sw.writeInterface();
-        sw.writeClassBegin(Type.getObjectType(JvmAbi.JET_OBJECT.getInternalName()));
-        sw.writeClassEnd();
-        sw.writeInterfaceEnd();
-        superInterfaces.add(JvmAbi.JET_OBJECT.getInternalName());
+        List<JetType> interfaceSupertypes = Lists.newArrayList();
+        FqNameUnsafe jetObjectFqName = JvmAbi.JET_OBJECT.getFqNameForClassNameWithoutDollars().toUnsafe();
+        boolean explicitJetObject = false;
 
         for (JetDelegationSpecifier specifier : myClass.getDelegationSpecifiers()) {
             JetType superType = bindingContext.get(BindingContext.TYPE, specifier.getTypeReference());
             assert superType != null : "No supertype for class: " + myClass.getText();
             ClassDescriptor superClassDescriptor = (ClassDescriptor) superType.getConstructor().getDeclarationDescriptor();
             if (isInterface(superClassDescriptor)) {
-                sw.writeInterface();
-                Type jvmName = typeMapper.mapSupertype(superType, sw);
-                sw.writeInterfaceEnd();
-                superInterfaces.add(jvmName.getInternalName());
+                interfaceSupertypes.add(superType);
+
+                assert superClassDescriptor != null : "should be already checked by isInterface()";
+                if (jetObjectFqName.equals(DescriptorUtils.getFqName(superClassDescriptor))) {
+                    explicitJetObject = true;
+                }
             }
         }
 
+        LinkedHashSet<String> superInterfaces = new LinkedHashSet<String>();
+        if (!explicitJetObject) {
+            sw.writeInterface();
+            sw.writeClassBegin(Type.getObjectType(JvmAbi.JET_OBJECT.getInternalName()));
+            sw.writeClassEnd();
+            sw.writeInterfaceEnd();
+            superInterfaces.add(JvmAbi.JET_OBJECT.getInternalName());
+        }
+
+        for (JetType supertype : interfaceSupertypes) {
+            sw.writeInterface();
+            Type jvmName = typeMapper.mapSupertype(supertype, sw);
+            sw.writeInterfaceEnd();
+            superInterfaces.add(jvmName.getInternalName());
+        }
+
         return new JvmClassSignature(classAsmType.getInternalName(), superClassAsmType.getInternalName(),
                                      new ArrayList<String>(superInterfaces),
                                      sw.makeJavaGenericSignature());
diff --git a/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt b/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt
index 62882c27798..d20e96e2b41 100644
--- a/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt
+++ b/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt
@@ -8,6 +8,10 @@ class ClassWithGenericSuperInterface: java.util.Comparator<String> {
     override fun compare(a: String, b: String): Int = 0
 }
 
+class ExplicitJetObject: java.util.Comparator<String>, JetObject {
+    override fun compare(a: String, b: String): Int = 0
+}
+
 fun check(klass: Class<*>) {
     val interfaces = klass.getInterfaces().toList()
     val genericInterfaces = klass.getGenericInterfaces().toList()
@@ -20,5 +24,6 @@ fun box(): String {
     check(javaClass<SimpleClass>())
     check(javaClass<ClassWithNonGenericSuperInterface>())
     check(javaClass<ClassWithGenericSuperInterface>())
+    check(javaClass<ExplicitJetObject>())
     return "OK"
 }
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