diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4250c46..c210b79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - `PsrToOrisaiClockAdapter` - makes any PSR clock compatible with `Orisai\Clock\Clock`
 - `SymfonyToOrisaiClockAdapter` - makes any symfony/clock compatible with `Orisai\Clock\Clock`
 - `ClockAdapterFactory` - chooses best supported adapter for `Orisai\Clock\Clock` compatibility
+- `FrozenClock` - accepts `DateTimeInterface` as the initial time
 
 ### Changed
 
diff --git a/docs/README.md b/docs/README.md
index 46c35eb..3dfffc2 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -130,6 +130,17 @@ use DateTimeZone;
 $clock = new FrozenClock(0, new DateTimeZone('UTC'));
 ```
 
+You can also create clock from datetime
+
+```php
+use DateTime;
+use DateTimeImmutable;
+
+$clock = new FrozenClock(new DateTimeImmutable());
+// or
+$clock = new FrozenClock(new DateTime());
+```
+
 [Sleeping](#sleep) does not put thread to sleep but just moves timestamp of clock's internal `DateTimeImmutable`.
 
 ### Measurement clock
diff --git a/src/FrozenClock.php b/src/FrozenClock.php
index 0578fc8..a7e5e32 100644
--- a/src/FrozenClock.php
+++ b/src/FrozenClock.php
@@ -2,7 +2,9 @@
 
 namespace Orisai\Clock;
 
+use DateTime;
 use DateTimeImmutable;
+use DateTimeInterface;
 use DateTimeZone;
 use function date_default_timezone_get;
 use function floor;
@@ -16,13 +18,22 @@ final class FrozenClock implements Clock
 
 	private DateTimeImmutable $dt;
 
-	public function __construct(float $timestamp, ?DateTimeZone $timeZone = null)
+	/**
+	 * @param float|DateTimeInterface $timestamp
+	 */
+	public function __construct($timestamp, ?DateTimeZone $timeZone = null)
 	{
-		[$seconds, $microseconds] = $this->getParts($timestamp);
+		if ($timestamp instanceof DateTime) {
+			$dt = DateTimeImmutable::createFromMutable($timestamp);
+		} elseif ($timestamp instanceof DateTimeImmutable) {
+			$dt = $timestamp;
+		} else {
+			[$seconds, $microseconds] = $this->getParts($timestamp);
+			$dt = DateTimeImmutable::createFromFormat('U', (string) $seconds)
+				->modify("+$microseconds microsecond");
+		}
 
-		$this->dt = DateTimeImmutable::createFromFormat('U', (string) $seconds)
-			->setTimezone($timeZone ?? new DateTimeZone(date_default_timezone_get()))
-			->modify("+$microseconds microsecond");
+		$this->dt = $dt->setTimezone($timeZone ?? new DateTimeZone(date_default_timezone_get()));
 	}
 
 	public function now(): DateTimeImmutable
diff --git a/tests/Unit/FrozenClockTest.php b/tests/Unit/FrozenClockTest.php
index b3d2a3d..7e4d840 100644
--- a/tests/Unit/FrozenClockTest.php
+++ b/tests/Unit/FrozenClockTest.php
@@ -2,7 +2,11 @@
 
 namespace Tests\Orisai\Clock\Unit;
 
+use DateTime;
+use DateTimeImmutable;
+use DateTimeInterface;
 use DateTimeZone;
+use Generator;
 use Orisai\Clock\FrozenClock;
 use PHPUnit\Framework\TestCase;
 use function date_default_timezone_get;
@@ -40,6 +44,35 @@ public function testFrozenTime(): void
 		self::assertSame('1.000000', $now);
 	}
 
+	/**
+	 * @param int|DateTimeInterface $datetime
+	 *
+	 * @dataProvider provideTimestampVariants
+	 */
+	public function testTimestampVariants($datetime, int $timestamp): void
+	{
+		$clock = new FrozenClock($datetime);
+		self::assertSame($timestamp, $clock->now()->getTimestamp());
+	}
+
+	public function provideTimestampVariants(): Generator
+	{
+		yield [
+			1,
+			1,
+		];
+
+		yield [
+			DateTimeImmutable::createFromFormat('U', '1'),
+			1,
+		];
+
+		yield [
+			DateTime::createFromFormat('U', '1'),
+			1,
+		];
+	}
+
 	public function testTimeDoesNotChange(): void
 	{
 		$clock = new FrozenClock(1);
diff --git a/tools/phpstan.baseline.neon b/tools/phpstan.baseline.neon
index c5e4667..a4adb95 100644
--- a/tools/phpstan.baseline.neon
+++ b/tools/phpstan.baseline.neon
@@ -1,13 +1,13 @@
 parameters:
 	ignoreErrors:
 		-
-			message: "#^Cannot call method setTimezone\\(\\) on DateTimeImmutable\\|false\\.$#"
+			message: "#^Cannot call method modify\\(\\) on DateTimeImmutable\\|false\\.$#"
 			count: 1
 			path: ../src/FrozenClock.php
 
 		-
 			message: "#^Property Orisai\\\\Clock\\\\FrozenClock\\:\\:\\$dt \\(DateTimeImmutable\\) does not accept \\(DateTimeImmutable\\|false\\)\\.$#"
-			count: 5
+			count: 4
 			path: ../src/FrozenClock.php
 
 		-
@@ -20,6 +20,11 @@ parameters:
 			count: 1
 			path: ../src/MeasurementClock.php
 
+		-
+			message: "#^Parameter \\#1 \\$now of class Symfony\\\\Component\\\\Clock\\\\MockClock constructor expects DateTimeImmutable\\|string, DateTimeImmutable\\|false given\\.$#"
+			count: 2
+			path: ../tests/Unit/Adapter/SymfonyToOrisaiClockAdapterTest.php
+
 		-
 			message: """
 				#^Call to deprecated method move\\(\\) of class Orisai\\\\Clock\\\\FrozenClock\\:
@@ -27,8 +32,3 @@ parameters:
 			"""
 			count: 9
 			path: ../tests/Unit/FrozenClockTest.php
-
-		-
-			message: "#^Parameter \\#1 \\$now of class Symfony\\\\Component\\\\Clock\\\\MockClock constructor expects DateTimeImmutable\\|string, DateTimeImmutable\\|false given\\.$#"
-			count: 2
-			path: ../tests/Unit/Adapter/SymfonyToOrisaiClockAdapterTest.php