diff --git a/roofit/roofitcore/inc/RooFormula.h b/roofit/roofitcore/inc/RooFormula.h
index b7a681e1cd885..4f8a7f5421e73 100644
--- a/roofit/roofitcore/inc/RooFormula.h
+++ b/roofit/roofitcore/inc/RooFormula.h
@@ -50,7 +50,7 @@ class RooFormula : public TNamed, public RooPrintable {
     return _origList.at(index);
   }
 
-  Bool_t ok() { return _tFormula != nullptr; }
+  Bool_t ok() const { return _tFormula != nullptr; }
   /// Evalute all parameters/observables, and then evaluate formula.
   Double_t eval(const RooArgSet* nset=0) const;
 
diff --git a/roofit/roofitcore/inc/RooFormulaVar.h b/roofit/roofitcore/inc/RooFormulaVar.h
index aefb2f628d3b1..2bc72c6c4c333 100644
--- a/roofit/roofitcore/inc/RooFormulaVar.h
+++ b/roofit/roofitcore/inc/RooFormulaVar.h
@@ -36,14 +36,14 @@ class RooFormulaVar : public RooAbsReal {
   RooFormulaVar(const RooFormulaVar& other, const char* name=0);
   virtual TObject* clone(const char* newname) const { return new RooFormulaVar(*this,newname); }
 
-  inline Bool_t ok() const { return formula().ok() ; }
+  inline Bool_t ok() const { return getFormula().ok() ; }
 
+  /// Return pointer to parameter with given name.
   inline RooAbsArg* getParameter(const char* name) const { 
-    // Return pointer to parameter with given name
     return _actualVars.find(name) ; 
   }
+  /// Return pointer to parameter at given index.
   inline RooAbsArg* getParameter(Int_t index) const { 
-    // Return pointer to parameter at given index
     return _actualVars.at(index) ; 
   }
 
@@ -56,7 +56,12 @@ class RooFormulaVar : public RooAbsReal {
   void printMetaArgs(std::ostream& os) const ;
 
   // Debugging
-  void dumpFormula() { formula().dump() ; }
+  /// Dump the formula to stdout.
+  void dumpFormula() { getFormula().dump() ; }
+  /// Get reference to the internal formula object.
+  const RooFormula& formula() const {
+    return getFormula();
+  }
 
   virtual Double_t defaultErrorLevel() const ;
 
@@ -73,7 +78,7 @@ class RooFormulaVar : public RooAbsReal {
   virtual Bool_t isValidReal(Double_t /*value*/, Bool_t /*printError*/) const {return true;}
 
   private:
-  RooFormula& formula() const;
+  RooFormula& getFormula() const;
 
   RooListProxy _actualVars ;     // Actual parameters used by formula engine
   std::unique_ptr<RooFormula> _formula{nullptr}; //! Formula engine
diff --git a/roofit/roofitcore/src/RooFormulaVar.cxx b/roofit/roofitcore/src/RooFormulaVar.cxx
index 947c50559874a..80da4c12fe526 100644
--- a/roofit/roofitcore/src/RooFormulaVar.cxx
+++ b/roofit/roofitcore/src/RooFormulaVar.cxx
@@ -128,7 +128,8 @@ RooFormulaVar::RooFormulaVar(const RooFormulaVar& other, const char* name) :
 
 ////////////////////////////////////////////////////////////////////////////////
 /// Return reference to internal RooFormula object.
-RooFormula& RooFormulaVar::formula() const
+/// If it doesn't exist, create it on the fly.
+RooFormula& RooFormulaVar::getFormula() const
 {
   if (!_formula) {
     // After being read from file, the formula object might not exist, yet:
@@ -147,7 +148,7 @@ RooFormula& RooFormulaVar::formula() const
 
 Double_t RooFormulaVar::evaluate() const
 {
-  return formula().eval(_lastNSet);
+  return getFormula().eval(_lastNSet);
 }
 
 
@@ -156,9 +157,9 @@ Double_t RooFormulaVar::evaluate() const
 
 Bool_t RooFormulaVar::redirectServersHook(const RooAbsCollection& newServerList, Bool_t mustReplaceAll, Bool_t nameChange, Bool_t /*isRecursive*/)
 {
-  bool success = formula().changeDependents(newServerList,mustReplaceAll,nameChange);
+  bool success = getFormula().changeDependents(newServerList,mustReplaceAll,nameChange);
 
-  _formExpr = formula().GetTitle();
+  _formExpr = getFormula().GetTitle();
   return success;
 }
 
@@ -173,7 +174,7 @@ void RooFormulaVar::printMultiline(ostream& os, Int_t contents, Bool_t verbose,
   if(verbose) {
     indent.Append("  ");
     os << indent;
-    formula().printMultiline(os,contents,verbose,indent);
+    getFormula().printMultiline(os,contents,verbose,indent);
   }
 }