diff --git a/R/dup.R b/R/dup.R
index 2cf3ddab..3a82ffe0 100644
--- a/R/dup.R
+++ b/R/dup.R
@@ -11,6 +11,7 @@
 #' @examples
 #' fruit <- c("apple", "pear", "banana")
 #' str_dup(fruit, 2)
+#' str_dup(fruit, 2, sep = " ")
 #' str_dup(fruit, 1:3)
 #' str_c("ba", str_dup("na", 0:5))
 str_dup <- function(string, times, sep = NULL) {
@@ -21,7 +22,7 @@ str_dup <- function(string, times, sep = NULL) {
     stri_dup(input$string, input$times)
   } else {
     map_chr(seq_along(input$string), function(i) {
-      paste(rep(string[i], input$times[i]), collapse = sep)
+      paste(rep(string[[i]], input$times[[i]]), collapse = sep)
     })
   }
 }
diff --git a/man/str_dup.Rd b/man/str_dup.Rd
index a2e2e162..48a7867b 100644
--- a/man/str_dup.Rd
+++ b/man/str_dup.Rd
@@ -24,6 +24,7 @@ A character vector the same length as \code{string}/\code{times}.
 \examples{
 fruit <- c("apple", "pear", "banana")
 str_dup(fruit, 2)
+str_dup(fruit, 2, sep = " ")
 str_dup(fruit, 1:3)
 str_c("ba", str_dup("na", 0:5))
 }