diff --git a/bar.go b/bar.go
index 41b2487..2eb74e2 100644
--- a/bar.go
+++ b/bar.go
@@ -17,7 +17,7 @@
 // Filler interface.
 // Bar renders by calling Filler's Fill method. You can literally have
 // any bar kind, by implementing this interface and passing it to the
-// mpb.Add function.
+// *Progress.Add method.
 type Filler interface {
 	Fill(w io.Writer, width int, stat *decor.Statistics)
 }
@@ -27,6 +27,14 @@
 
 func (f FillerFunc) Fill(w io.Writer, width int, stat *decor.Statistics) {
 	f(w, width, stat)
+}
+
+// BaseFiller interface.
+// If you ever need to implement a custom Filler based on mpb.NewBarFiller,
+// then you may need to implement this one as well, in order to retain
+// functionality of some `BarOption`s and method like *Bar.SetRefill.
+type BaseFiller interface {
+	BaseFiller() Filler
 }
 
 // Bar represents a progress Bar.
diff --git a/progress.go b/progress.go
index d6ed3f2..4a0f3c1 100644
--- a/progress.go
+++ b/progress.go
@@ -343,6 +343,10 @@
 		},
 	}
 
+	if f, ok := filler.(BaseFiller); ok {
+		bs.baseF = f.BaseFiller()
+	}
+
 	for _, opt := range options {
 		if opt != nil {
 			opt(bs)