diff --git a/ExtendedPromQL.md b/ExtendedPromQL.md
index 0167f4f..f34ee9a 100644
--- a/ExtendedPromQL.md
+++ b/ExtendedPromQL.md
@@ -34,3 +34,4 @@ Try these extensions on [an editable Grafana dashboard](http://play-grafana.vict
 - `median_over_time(m[d])` - calculates median values for `m` over `d` time window. Shorthand to `quantile_over_time(0.5, m[d])`.
 - `median(q)` - median aggregate. Shorthand to `quantile(0.5, q)`.
 - `limitk(k, q)` - limits the number of time series returned from `q` to `k`.
+- `keep_last_value(q)` - fills missing data (gaps) in `q` with the previous value.