Are gifts to a fiancée before the wedding but in the same year subject to gift tax reporting?

Assume both future spouses are U.S. citizens and the wedding will be in September 2025. If one of them gives $20k to the other in June 2025, does a form 709 need to be filed with their joint married 2025 return, or does the unlimited spouse exemption apply for the entire calendar year of the wedding?