diff --git a/src/humanize/time.py b/src/humanize/time.py
index 4a07d52..a36f3b1 100644
--- a/src/humanize/time.py
+++ b/src/humanize/time.py
@@ -61,9 +61,9 @@ def _abs_timedelta(delta: dt.timedelta) -> dt.timedelta:
     Returns:
         datetime.timedelta: Absolute timedelta.
     """
+    # Avoid datetime arithmetic: now+(now-far_future) underflows below year 1.
     if delta.days < 0:
-        now = _now()
-        return now - (now + delta)
+        return -delta
     return delta
 
 
diff --git a/tests/test_time.py b/tests/test_time.py
index 7699770..22a276a 100644
--- a/tests/test_time.py
+++ b/tests/test_time.py
@@ -179,6 +179,10 @@ def test_naturaldelta(test_input: float | dt.timedelta, expected: str) -> None:
         (NOW - dt.timedelta(days=365 * 2 + 65), "2 years ago"),
         (NOW - dt.timedelta(days=365 + 4), "1 year, 4 days ago"),
         ("NaN", "NaN"),
+        # Far-future datetimes used to OverflowError in _abs_timedelta.
+        (dt.datetime(9999, 1, 1), "7,994 years from now"),
+        (dt.datetime(5000, 6, 15), "2,992 years from now"),
+        (dt.timedelta(days=-1_000_000), "2,739 years from now"),
     ],
 )
 def test_naturaltime(