diff --git a/R/backend-dbplyr__duckdb_connection.R b/R/backend-dbplyr__duckdb_connection.R
index 6c4f390c4..32a4e07e0 100644
--- a/R/backend-dbplyr__duckdb_connection.R
+++ b/R/backend-dbplyr__duckdb_connection.R
@@ -79,6 +79,12 @@ duckdb_grepl <- function(pattern, x, ignore.case = FALSE, perl = FALSE, fixed =
 
 duckdb_n_distinct <- function(..., na.rm = FALSE) {
   sql <- pkg_method("sql", "dbplyr")
+  check_dots_unnamed <- pkg_method("check_dots_unnamed", "rlang")
+
+  if (missing(...)) {
+    stop("`...` is absent, but must be supplied.")
+  }
+  check_dots_unnamed()
 
   if (!identical(na.rm, FALSE)) {
     stop("Parameter `na.rm = TRUE` in n_distinct() is currently not supported in DuckDB backend.", call. = FALSE)
diff --git a/tests/testthat/test-backend-dbplyr__duckdb_connection.R b/tests/testthat/test-backend-dbplyr__duckdb_connection.R
index 7254dba81..4db5c6eef 100644
--- a/tests/testthat/test-backend-dbplyr__duckdb_connection.R
+++ b/tests/testthat/test-backend-dbplyr__duckdb_connection.R
@@ -284,6 +284,7 @@ test_that("n_distinct() computations are correct", {
   on.exit(dbDisconnect(con, shutdown = TRUE))
   tbl <- dplyr::tbl
   summarize <- dplyr::summarize
+  mutate <- dplyr::mutate
   pull <- dplyr::pull
 
   duckdb_register(con, "df", data.frame(x = c(1, 1, 2, 2), y = c(1, 2, 2, 2)))
@@ -318,6 +319,11 @@ test_that("n_distinct() computations are correct", {
     pull(summarize(df_na, n = n_distinct(x, y)), n),
     5
   )
+
+  expect_equal(
+    pull(mutate(df_na, n = n_distinct(x, y)), n),
+    rep(5, 5)
+  )
 })