what is the best way to read a large xml file in a singleton class

I have a singleton class which read some properties from a xml file which has quite a huge number of elements.Currently, I am reading the xml file inside the constructor of the singleton class. once the entries in the xml is read, I can access those from the singleton instance without having to read the xml again and again. I would like to know if this is a correct approach or is there better way to get it done than this.