Sometime later this season Idina Menzel will guest star on Private Practice. I do not usually watch this show, but it may be interesting to see her in it.
My guess is it won't be about Idina coming to see Audra's character about anything fertility related--too close to home for her and Taye. Though it would been fun to see her and Audra go head to head in an Eli Stone or Pushing Daisies style musical interlude.
From what I heard she will be playing a mother of a child who goes to see Dr. Pete (Tim Daly). He is an acupuncturist in the practice and apparently she will be in a few episodes because she is supposed to become a possible love interest for Tim Daly's character.
I believe her arc begins this coming week since the episode description says Pete begins dating a patient's fun mother and that aligns with the previous description about her role.