diff --git a/resources/js/components/field-validation/Builder.vue b/resources/js/components/field-validation/Builder.vue
index 5da152c8084..beaf4635351 100644
--- a/resources/js/components/field-validation/Builder.vue
+++ b/resources/js/components/field-validation/Builder.vue
@@ -47,7 +47,7 @@
                     />
                 </template>
                 <template #option="{ value, display }">
-                    {{ display }} <code class="ml-1">{{ value.replace(':', '') }}</code>
+                    {{ display }} <code class="ml-1">{{ valueWithoutTrailingColon(value) }}</code>
                 </template>
                 <template #no-options="{ search }">
                     <div class="vs__dropdown-option text-left">{{ __('Add') }} <code class="ml-1">{{ search }}</code></div>
@@ -253,6 +253,10 @@ export default {
             this.rules = rules;
         },
 
+        valueWithoutTrailingColon(value) {
+            return this.hasUnfinishedParameters(value) ? value.replace(':', '') : value;
+        }
+
     }
 }
 </script>
diff --git a/resources/js/components/field-validation/Rules.js b/resources/js/components/field-validation/Rules.js
index e5000917890..fd1b8e99061 100644
--- a/resources/js/components/field-validation/Rules.js
+++ b/resources/js/components/field-validation/Rules.js
@@ -286,6 +286,10 @@ export default [
     //     value: 'unique:',
     //     example: 'unique:table,column,except,idColumn'
     // },
+    {
+        label: 'Unique Entry Value',
+        value: 'unique_entry_value:{collection},{id},{site}',
+    },
     {
         label: 'URL',
         value: 'url'
diff --git a/src/Fields/Validator.php b/src/Fields/Validator.php
index e0d194255c6..59b5a4c5562 100644
--- a/src/Fields/Validator.php
+++ b/src/Fields/Validator.php
@@ -4,11 +4,13 @@
 
 use Illuminate\Support\Facades\Lang;
 use Illuminate\Support\Facades\Validator as LaravelValidator;
+use Statamic\Support\Arr;
+use Statamic\Support\Str;
 
 class Validator
 {
     protected $fields;
-    protected $data = [];
+    protected $replacements = [];
     protected $extraRules = [];
 
     public function make()
@@ -34,7 +36,11 @@ public function rules()
     {
         return $this
             ->merge($this->fieldRules(), $this->extraRules)
-            ->all();
+            ->map(function ($rules) {
+                return collect($rules)->map(function ($rule) {
+                    return $this->parse($rule);
+                })->all();
+            })->all();
     }
 
     private function fieldRules()
@@ -65,6 +71,13 @@ public function merge($original, $overrides)
         return collect($original);
     }
 
+    public function withReplacements($replacements)
+    {
+        $this->replacements = $replacements;
+
+        return $this;
+    }
+
     public function validate()
     {
         return LaravelValidator::validate(
@@ -84,6 +97,17 @@ private function fieldAttributes()
         })->all();
     }
 
+    private function parse($rule)
+    {
+        if (! Str::contains($rule, '{')) {
+            return $rule;
+        }
+
+        return preg_replace_callback('/{\s*([a-zA-Z0-9_\-]+)\s*}/', function ($match) {
+            return Arr::get($this->replacements, $match[1], 'NULL');
+        }, $rule);
+    }
+
     public static function explodeRules($rules)
     {
         if (! $rules) {
diff --git a/src/Http/Controllers/CP/Collections/EntriesController.php b/src/Http/Controllers/CP/Collections/EntriesController.php
index 7974b10f8d3..118a2b0aca9 100644
--- a/src/Http/Controllers/CP/Collections/EntriesController.php
+++ b/src/Http/Controllers/CP/Collections/EntriesController.php
@@ -164,7 +164,14 @@ public function update(Request $request, $collection, $entry)
 
         $fields = $entry->blueprint()->fields()->addValues($data);
 
-        $fields->validate(Entry::updateRules($collection, $entry));
+        $fields
+            ->validator()
+            ->withRules(Entry::updateRules($collection, $entry))
+            ->withReplacements([
+                'id' => $entry->id(),
+                'collection' => $collection->handle(),
+                'site' => $entry->locale(),
+            ])->validate();
 
         $values = $fields->process()->values();
 
@@ -302,7 +309,13 @@ public function store(Request $request, $collection, $site)
 
         $fields = $blueprint->fields()->addValues($data);
 
-        $fields->validate(Entry::createRules($collection, $site));
+        $fields
+            ->validator()
+            ->withRules(Entry::createRules($collection, $site))
+            ->withReplacements([
+                'collection' => $collection->handle(),
+                'site' => $site->handle(),
+            ])->validate();
 
         $values = $fields->process()->values()->except(['slug', 'date', 'blueprint']);
 
diff --git a/tests/Fields/ValidatorTest.php b/tests/Fields/ValidatorTest.php
index a600ef03185..3dc8447500b 100644
--- a/tests/Fields/ValidatorTest.php
+++ b/tests/Fields/ValidatorTest.php
@@ -116,4 +116,32 @@ public function it_merges_additional_rules_into_field_rules()
             'additional' => ['required'],
         ], $validation->rules());
     }
+
+    /** @test */
+    public function it_makes_replacements()
+    {
+        $field = Mockery::mock(Field::class);
+        $field->shouldReceive('rules')->andReturn([
+            'one' => ['required', 'test:{foo}'],
+        ]);
+
+        $fields = Mockery::mock(Fields::class);
+        $fields->shouldReceive('all')->andReturn(collect([$field]));
+        $fields->shouldReceive('preProcessValidatables')->andReturnSelf();
+
+        $validation = (new Validator)->fields($fields)->withRules([
+            'one' => 'test:{bar}',
+            'two' => 'another:{baz},{qux},{quux}',
+        ])->withReplacements([
+            'foo' => 'FOO',
+            'bar' => 'BAR',
+            'baz' => 'BAZ',
+            'quux' => 'QUUX',
+        ]);
+
+        $this->assertEquals([
+            'one' => ['required', 'test:FOO', 'test:BAR'],
+            'two' => ['another:BAZ,NULL,QUUX'],
+        ], $validation->rules());
+    }
 }