Fetch values of current form to fill values of a new entry form within

Fetch values of current form to fill values of a new entry form within

Hi, I have a form called ADD with a date field Date1. And in ADD there is a lookup field to a  Create Invoice form . In Create Invoice there is a Date1 field. When I click "Add New" in the Create Invoice lookup to create a new entry, I would like the Date1 field to equal the Date_of_Event field from ADD. How do I accomplish this? ( Date1 and Date_of_Event are both date fields)