diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
index 6057fa9a4e8..4f611e1f2cc 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
@@ -878,6 +878,7 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val LATEINIT_PROPERTY_FIELD_DECLARATION_WITH_INITIALIZER by error<KtBackingField>(PositioningStrategy.LATEINIT_MODIFIER)
         val LATEINIT_FIELD_IN_VAL_PROPERTY by error<KtBackingField>(PositioningStrategy.LATEINIT_MODIFIER)
         val LATEINIT_NULLABLE_BACKING_FIELD by error<KtBackingField>(PositioningStrategy.LATEINIT_MODIFIER)
+        val BACKING_FIELD_FOR_DELEGATED_PROPERTY by error<KtBackingField>(PositioningStrategy.FIELD_KEYWORD)
         val PROPERTY_MUST_HAVE_GETTER by error<KtProperty>()
         val PROPERTY_MUST_HAVE_SETTER by error<KtProperty>()
         val EXPLICIT_BACKING_FIELD_IN_INTERFACE by error<KtBackingField>(PositioningStrategy.FIELD_KEYWORD)
diff --git a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
index 44b43259ed0..bda4e94b0ad 100644
--- a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
+++ b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
@@ -485,6 +485,7 @@ object FirErrors {
     val LATEINIT_PROPERTY_FIELD_DECLARATION_WITH_INITIALIZER by error0<KtBackingField>(SourceElementPositioningStrategies.LATEINIT_MODIFIER)
     val LATEINIT_FIELD_IN_VAL_PROPERTY by error0<KtBackingField>(SourceElementPositioningStrategies.LATEINIT_MODIFIER)
     val LATEINIT_NULLABLE_BACKING_FIELD by error0<KtBackingField>(SourceElementPositioningStrategies.LATEINIT_MODIFIER)
+    val BACKING_FIELD_FOR_DELEGATED_PROPERTY by error0<KtBackingField>(SourceElementPositioningStrategies.FIELD_KEYWORD)
     val PROPERTY_MUST_HAVE_GETTER by error0<KtProperty>()
     val PROPERTY_MUST_HAVE_SETTER by error0<KtProperty>()
     val EXPLICIT_BACKING_FIELD_IN_INTERFACE by error0<KtBackingField>(SourceElementPositioningStrategies.FIELD_KEYWORD)
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirPropertyFieldDeclarationChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirPropertyFieldDeclarationChecker.kt
index f07a2a4351a..5914331dc53 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirPropertyFieldDeclarationChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirPropertyFieldDeclarationChecker.kt
@@ -53,6 +53,10 @@ object FirPropertyFieldTypeChecker : FirPropertyChecker() {
             reporter.reportOn(backingField.source, FirErrors.LATEINIT_NULLABLE_BACKING_FIELD, context)
         }
 
+        if (declaration.delegate != null) {
+            reporter.reportOn(backingField.source, FirErrors.BACKING_FIELD_FOR_DELEGATED_PROPERTY, context)
+        }
+
         if (backingField.returnTypeRef.coneType == declaration.returnTypeRef.coneType) {
             reporter.reportOn(backingField.source, FirErrors.REDUNDANT_EXPLICIT_BACKING_FIELD, context)
             return
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
index d0518fdb852..c03841d4770 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
@@ -70,6 +70,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ASSIGNING_SINGLE_
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ASSIGNMENT_TYPE_MISMATCH
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ASSIGN_OPERATOR_AMBIGUITY
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.BACKING_FIELD_FOR_DELEGATED_PROPERTY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.BACKING_FIELD_IN_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.BOUNDS_NOT_ALLOWED_IF_BOUNDED_BY_TYPE_PARAMETER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.BOUND_ON_TYPE_ALIAS_PARAMETER_NOT_ALLOWED
@@ -1298,6 +1299,10 @@ class FirDefaultErrorMessages {
                 LATEINIT_NULLABLE_BACKING_FIELD,
                 "Lateinit modifier is not allowed on backing fields of a type with nullable upper bound"
             )
+            map.put(
+                BACKING_FIELD_FOR_DELEGATED_PROPERTY,
+                "Delegated properties can't have explicit backing field declarations"
+            )
             map.put(
                 PROPERTY_MUST_HAVE_GETTER,
                 "This property needs a custom getter, because it's type is not a supertype of the backing field's type"
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt
index 3bb99d41798..45123e58e58 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt
@@ -2436,6 +2436,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.BACKING_FIELD_FOR_DELEGATED_PROPERTY) { firDiagnostic ->
+        BackingFieldForDelegatedPropertyImpl(
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.PROPERTY_MUST_HAVE_GETTER) { firDiagnostic ->
         PropertyMustHaveGetterImpl(
             firDiagnostic as FirPsiDiagnostic,
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt
index d31d5fc2d59..83effb7fa7a 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt
@@ -1723,6 +1723,10 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = LateinitNullableBackingField::class
     }
 
+    abstract class BackingFieldForDelegatedProperty : KtFirDiagnostic<KtBackingField>() {
+        override val diagnosticClass get() = BackingFieldForDelegatedProperty::class
+    }
+
     abstract class PropertyMustHaveGetter : KtFirDiagnostic<KtProperty>() {
         override val diagnosticClass get() = PropertyMustHaveGetter::class
     }
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
index b4d37736601..529b4a997c6 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
@@ -2774,6 +2774,13 @@ internal class LateinitNullableBackingFieldImpl(
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }
 
+internal class BackingFieldForDelegatedPropertyImpl(
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.BackingFieldForDelegatedProperty(), KtAbstractFirDiagnostic<KtBackingField> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
 internal class PropertyMustHaveGetterImpl(
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,