diff --git a/R/grouped-df.r b/R/grouped-df.r
index b7048a3d30..1df11a0c27 100644
--- a/R/grouped-df.r
+++ b/R/grouped-df.r
@@ -194,7 +194,7 @@ group_sum <- function(x) {
 }
 
 #' @export
-tbl_sum.grouped_df <- function(x) {
+tbl_sum.grouped_df <- function(x, ...) {
   c(
     NextMethod(),
     c("Groups" = group_sum(x))
diff --git a/R/rowwise.r b/R/rowwise.r
index 7e933110f8..6f3d75217e 100644
--- a/R/rowwise.r
+++ b/R/rowwise.r
@@ -127,7 +127,7 @@ setOldClass(c("rowwise_df", "tbl_df", "tbl", "data.frame"))
 # methods -----------------------------------------------------------------
 
 #' @export
-tbl_sum.rowwise_df <- function(x) {
+tbl_sum.rowwise_df <- function(x, ...) {
   c(
     NextMethod(),
     "Rowwise" = commas(group_vars(x))