diff --git a/samples/net/echo_client/src/udp.c b/samples/net/echo_client/src/udp.c
index 946c5215d29..eec045a1767 100644
--- a/samples/net/echo_client/src/udp.c
+++ b/samples/net/echo_client/src/udp.c
@@ -254,7 +254,7 @@ static void udp_connected(struct net_app_ctx *ctx,
 static int connect_udp(struct net_app_ctx *ctx, const char *peer,
 		       void *user_data, u8_t *dtls_result_buf,
 		       size_t dtls_result_buf_len,
-		       u8_t *stack, size_t stack_size)
+		       k_thread_stack_t *stack, size_t stack_size)
 {
 	struct data *data = user_data;
 	int ret;