diff --git a/prometheus/histogram.go b/prometheus/histogram.go
index 56a54aa..331783a 100644
--- a/prometheus/histogram.go
+++ b/prometheus/histogram.go
@@ -387,7 +387,7 @@ func (v *HistogramVec) With(labels Labels) Observer {
 // vectors behave identically in terms of collection. Only one must be
 // registered with a given registry (usually the uncurried version). The Reset
 // method deletes all metrics, even if called on a curried vector.
-func (v *HistogramVec) CurryWith(labels Labels) (*HistogramVec, error) {
+func (v *HistogramVec) CurryWith(labels Labels) (ObserverVec, error) {
 	vec, err := v.curryWith(labels)
 	if vec != nil {
 		return &HistogramVec{vec}, err
@@ -397,7 +397,7 @@ func (v *HistogramVec) CurryWith(labels Labels) (*HistogramVec, error) {
 
 // MustCurryWith works as CurryWith but panics where CurryWith would have
 // returned an error.
-func (v *HistogramVec) MustCurryWith(labels Labels) *HistogramVec {
+func (v *HistogramVec) MustCurryWith(labels Labels) ObserverVec {
 	vec, err := v.CurryWith(labels)
 	if err != nil {
 		panic(err)
diff --git a/prometheus/observer.go b/prometheus/observer.go
index b0520e8..5806cd0 100644
--- a/prometheus/observer.go
+++ b/prometheus/observer.go
@@ -45,6 +45,8 @@ type ObserverVec interface {
 	GetMetricWithLabelValues(lvs ...string) (Observer, error)
 	With(Labels) Observer
 	WithLabelValues(...string) Observer
+	CurryWith(Labels) (ObserverVec, error)
+	MustCurryWith(Labels) ObserverVec
 
 	Collector
 }
diff --git a/prometheus/summary.go b/prometheus/summary.go
index cc0452a..f7dc85b 100644
--- a/prometheus/summary.go
+++ b/prometheus/summary.go
@@ -504,7 +504,7 @@ func (v *SummaryVec) With(labels Labels) Observer {
 // vectors behave identically in terms of collection. Only one must be
 // registered with a given registry (usually the uncurried version). The Reset
 // method deletes all metrics, even if called on a curried vector.
-func (v *SummaryVec) CurryWith(labels Labels) (*SummaryVec, error) {
+func (v *SummaryVec) CurryWith(labels Labels) (ObserverVec, error) {
 	vec, err := v.curryWith(labels)
 	if vec != nil {
 		return &SummaryVec{vec}, err
@@ -514,7 +514,7 @@ func (v *SummaryVec) CurryWith(labels Labels) (*SummaryVec, error) {
 
 // MustCurryWith works as CurryWith but panics where CurryWith would have
 // returned an error.
-func (v *SummaryVec) MustCurryWith(labels Labels) *SummaryVec {
+func (v *SummaryVec) MustCurryWith(labels Labels) ObserverVec {
 	vec, err := v.CurryWith(labels)
 	if err != nil {
 		panic(err)