How to prefix Plus sign "+" before the number if the value is negative in Google Sheets or MS Excel?

I am trying to add/prefix a plus sign "+" if the value is negative. e.g. +10

I have sheet where some bill payments are made and sometimes they overpay. So, the Balance column should reflect like +(over paid value).

I tried with =CONCATENATE but this does not help. It comes as +-10

=IF(C2<0,CONCATENATE("+",C2),"")