diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0b4fcad..61a5be8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,6 +61,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 * Add `getTime()` method to `Provider\TimeProviderInterface`.
 * Change `Uuid::getFields()` to return an instance of `Fields\FieldsInterface`.
   Previously, it returned an array of integer values (on 64-bit systems only).
+* Change the first required constructor parameter for `Uuid` from
+  `array $fields` to `Rfc4122\FieldsInterface $fields`.
 * Introduce `Converter\TimeConverterInterface $timeConverter` as fourth required
   constructor parameter for `Uuid` and second required constructor parameter for
   `Builder\DefaultUuidBuilder`.
diff --git a/src/Builder/DefaultUuidBuilder.php b/src/Builder/DefaultUuidBuilder.php
index dddbec1..086c01e 100644
--- a/src/Builder/DefaultUuidBuilder.php
+++ b/src/Builder/DefaultUuidBuilder.php
@@ -18,6 +18,7 @@ use Ramsey\Uuid\Codec\CodecInterface;
 use Ramsey\Uuid\Converter\NumberConverterInterface;
 use Ramsey\Uuid\Converter\TimeConverterInterface;
 use Ramsey\Uuid\Math\CalculatorInterface;
+use Ramsey\Uuid\Rfc4122\Fields as Rfc4122Fields;
 use Ramsey\Uuid\Uuid;
 use Ramsey\Uuid\UuidInterface;
 
@@ -73,6 +74,8 @@ class DefaultUuidBuilder implements UuidBuilderInterface
      */
     public function build(CodecInterface $codec, array $fields): UuidInterface
     {
+        $fields = new Rfc4122Fields((string) hex2bin(implode('', $fields)));
+
         return new Uuid(
             $fields,
             $this->numberConverter,
diff --git a/src/Builder/DegradedUuidBuilder.php b/src/Builder/DegradedUuidBuilder.php
index 212752f..907ab4a 100644
--- a/src/Builder/DegradedUuidBuilder.php
+++ b/src/Builder/DegradedUuidBuilder.php
@@ -21,6 +21,7 @@ use Ramsey\Uuid\Converter\TimeConverterInterface;
 use Ramsey\Uuid\DegradedUuid;
 use Ramsey\Uuid\Math\BrickMathCalculator;
 use Ramsey\Uuid\Math\CalculatorInterface;
+use Ramsey\Uuid\Rfc4122\Fields as Rfc4122Fields;
 use Ramsey\Uuid\UuidInterface;
 
 /**
@@ -68,13 +69,14 @@ class DegradedUuidBuilder implements UuidBuilderInterface
      * Builds and returns a DegradedUuid
      *
      * @param CodecInterface $codec The codec to use for building this DegradedUuid instance
-     * @param string[] $fields An array of fields from which to construct a DegradedUuid instance;
-     *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure.
+     * @param string[] $fields An array of fields from which to construct a DegradedUuid instance
      *
      * @return DegradedUuid The DegradedUuidBuild returns an instance of Ramsey\Uuid\DegradedUuid
      */
     public function build(CodecInterface $codec, array $fields): UuidInterface
     {
+        $fields = new Rfc4122Fields((string) hex2bin(implode('', $fields)));
+
         return new DegradedUuid(
             $fields,
             $this->numberConverter,
diff --git a/src/Builder/UuidBuilderInterface.php b/src/Builder/UuidBuilderInterface.php
index 06df7ec..2aff20a 100644
--- a/src/Builder/UuidBuilderInterface.php
+++ b/src/Builder/UuidBuilderInterface.php
@@ -28,8 +28,7 @@ interface UuidBuilderInterface
      * Builds and returns a UuidInterface
      *
      * @param CodecInterface $codec The codec to use for building this UuidInterface instance
-     * @param string[] $fields An array of fields from which to construct a UuidInterface instance;
-     *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure.
+     * @param string[] $fields An array of fields from which to construct a UuidInterface instance
      *
      * @return UuidInterface Implementations may choose to return more specific
      *     instances of UUIDs that implement UuidInterface
diff --git a/src/Guid/Guid.php b/src/Guid/Guid.php
index 093f978..2107e67 100644
--- a/src/Guid/Guid.php
+++ b/src/Guid/Guid.php
@@ -37,20 +37,13 @@ use Ramsey\Uuid\UuidInterface;
  */
 class Guid extends Uuid implements UuidInterface
 {
-    /**
-     * @param string[] $fields
-     */
     public function __construct(
-        array $fields,
+        Fields $fields,
         NumberConverterInterface $numberConverter,
         CodecInterface $codec,
         TimeConverterInterface $timeConverter,
         CalculatorInterface $calculator
     ) {
-        $this->fields = new Fields((string) hex2bin(implode('', $fields)));
-        $this->codec = $codec;
-        $this->numberConverter = $numberConverter;
-        $this->timeConverter = $timeConverter;
-        $this->calculator = $calculator;
+        parent::__construct($fields, $numberConverter, $codec, $timeConverter, $calculator);
     }
 }
diff --git a/src/Guid/GuidBuilder.php b/src/Guid/GuidBuilder.php
index 4fc5e31..5451f98 100644
--- a/src/Guid/GuidBuilder.php
+++ b/src/Guid/GuidBuilder.php
@@ -71,6 +71,8 @@ class GuidBuilder implements UuidBuilderInterface
      */
     public function build(CodecInterface $codec, array $fields): UuidInterface
     {
+        $fields = new Fields((string) hex2bin(implode('', $fields)));
+
         return new Guid(
             $fields,
             $this->numberConverter,
diff --git a/src/Nonstandard/Uuid.php b/src/Nonstandard/Uuid.php
index 616d4cd..68eb0a0 100644
--- a/src/Nonstandard/Uuid.php
+++ b/src/Nonstandard/Uuid.php
@@ -28,20 +28,13 @@ use Ramsey\Uuid\UuidInterface;
  */
 class Uuid extends Rfc4122Uuid implements UuidInterface
 {
-    /**
-     * @param string[] $fields
-     */
     public function __construct(
-        array $fields,
+        Fields $fields,
         NumberConverterInterface $numberConverter,
         CodecInterface $codec,
         TimeConverterInterface $timeConverter,
         CalculatorInterface $calculator
     ) {
-        $this->fields = new Fields((string) hex2bin(implode('', $fields)));
-        $this->codec = $codec;
-        $this->numberConverter = $numberConverter;
-        $this->timeConverter = $timeConverter;
-        $this->calculator = $calculator;
+        parent::__construct($fields, $numberConverter, $codec, $timeConverter, $calculator);
     }
 }
diff --git a/src/Nonstandard/UuidBuilder.php b/src/Nonstandard/UuidBuilder.php
index 961940c..b351ea1 100644
--- a/src/Nonstandard/UuidBuilder.php
+++ b/src/Nonstandard/UuidBuilder.php
@@ -72,6 +72,8 @@ class UuidBuilder implements UuidBuilderInterface
      */
     public function build(CodecInterface $codec, array $fields): UuidInterface
     {
+        $fields = new Fields((string) hex2bin(implode('', $fields)));
+
         return new Uuid(
             $fields,
             $this->numberConverter,
diff --git a/src/Uuid.php b/src/Uuid.php
index 1c32a26..7d8db73 100644
--- a/src/Uuid.php
+++ b/src/Uuid.php
@@ -23,7 +23,6 @@ use Ramsey\Uuid\Exception\DateTimeException;
 use Ramsey\Uuid\Exception\UnsupportedOperationException;
 use Ramsey\Uuid\Fields\FieldsInterface;
 use Ramsey\Uuid\Math\CalculatorInterface;
-use Ramsey\Uuid\Rfc4122\Fields;
 use Ramsey\Uuid\Rfc4122\FieldsInterface as Rfc4122FieldsInterface;
 
 /**
@@ -192,8 +191,7 @@ class Uuid implements UuidInterface
      * $namespaceSha1Uuid = Uuid::uuid5(Uuid::NAMESPACE_URL, 'http://php.net/');
      * ```
      *
-     * @param string[] $fields An array of fields from which to construct a UUID;
-     *     see {@see \Ramsey\Uuid\UuidInterface::getFieldsHex()} for array structure
+     * @param Rfc4122FieldsInterface $fields The fields from which to construct a UUID
      * @param NumberConverterInterface $numberConverter The number converter to use
      *     for converting hex values to/from integers
      * @param CodecInterface $codec The codec to use when encoding or decoding
@@ -204,13 +202,13 @@ class Uuid implements UuidInterface
      *     mathematical operations on UUIDs
      */
     public function __construct(
-        array $fields,
+        Rfc4122FieldsInterface $fields,
         NumberConverterInterface $numberConverter,
         CodecInterface $codec,
         TimeConverterInterface $timeConverter,
         CalculatorInterface $calculator
     ) {
-        $this->fields = new Fields((string) hex2bin(implode('', $fields)));
+        $this->fields = $fields;
         $this->codec = $codec;
         $this->numberConverter = $numberConverter;
         $this->timeConverter = $timeConverter;
diff --git a/tests/Codec/GuidStringCodecTest.php b/tests/Codec/GuidStringCodecTest.php
index df4bab0..f80a759 100644
--- a/tests/Codec/GuidStringCodecTest.php
+++ b/tests/Codec/GuidStringCodecTest.php
@@ -68,17 +68,9 @@ class GuidStringCodecTest extends TestCase
 
     public function testEncodeBinary(): void
     {
-        $expectedBytes = hex2bin('785634123412cd4babef1234abcd4321');
-
-        $fields = [
-            'time_low' => '78563412',
-            'time_mid' => '3412',
-            'time_hi_and_version' => 'cd4b',
-            'clock_seq_hi_and_reserved' => 'ab',
-            'clock_seq_low' => 'ef',
-            'node' => '1234abcd4321',
-        ];
+        $expectedBytes = (string) hex2bin('785634123412cd4babef1234abcd4321');
 
+        $fields = new Fields($expectedBytes);
         $codec = new GuidStringCodec($this->builder);
         $numberConverter = Mockery::mock(NumberConverterInterface::class);
         $timeConverter = Mockery::mock(TimeConverterInterface::class);