diff --git a/bar_option.go b/bar_option.go
index 64d2e18..b39628f 100644
--- a/bar_option.go
+++ b/bar_option.go
@@ -114,6 +114,9 @@
 	if filler == nil {
 		return nil
 	}
+	if f, ok := filler.(BarFillerFunc); ok && f == nil {
+		return nil
+	}
 	fn := makeExtenderFunc(filler, rev)
 	return func(s *bState) {
 		s.extender = fn
diff --git a/progress.go b/progress.go
index 42351a5..bbff7db 100644
--- a/progress.go
+++ b/progress.go
@@ -149,6 +149,8 @@
 // `(nil, DoneError)` is returned.
 func (p *Progress) Add(total int64, filler BarFiller, options ...BarOption) (*Bar, error) {
 	if filler == nil {
+		filler = NopStyle().Build()
+	} else if f, ok := filler.(BarFillerFunc); ok && f == nil {
 		filler = NopStyle().Build()
 	}
 	ch := make(chan *Bar)