G&S song to sing as a soprano duet?

Question:

Musical/G&S song to sing as a soprano duet?

Doing a concert with my local Amateur Operatic Society, looking for a duet to sing with another soprano. Was going to sing 'I Know Him So Well' from Chess, but not too sure about that choice. Anybody got any recommendations? Can be from any show/G&S/musical.

Best Answer - Chosen by Asker: Rope in a tenor and do "In My Life" from Les Mis.
"I still believe" or "Movie in My Mind" from Miss Saigon might be OK, but they go quite low for sops from what I remember (I think A below middle C).
The only other thing that springs to mind is "Pie Jesu" from Requiem (not strictly speaking a musical, but in that style).
Is there anything in Mamma Mia? Haven't seen that, but Abba a quite good for female duets, so they're might be something there.
Hope it goes well whatever you do.