It will be the first time that a South Korean JCS chairman has attended the ceremony. It comes amid speculation of a rift in the alliance after Seoul's decision last month to terminate a military information-sharing pact with Japan.

"Park decided to attend it as part of efforts to boost the South Korea-US alliance," the JCS said in a release.

The military leaders are expected to discuss the security situation on the Korean Peninsula and ways to further boost their alliance.

During the visit, Park will reportedly hold a trilateral meeting involving his US and Japanese counterparts, as Koji Yamazaki, who leads the Japan's Self-Defense forces, also plans to attend the event.

The three sides could discuss the General Security of Military Information Agreement between South Korea and Japan. Seoul's decision to end it followed Tokyo's imposition of export curbs on its neighbor in apparent retaliation against the South Korean top court's rulings on wartime forced labor.

The US has called on South Korea to withdraw the decision, and Tokyo also wants to keep the pact intact, while the Seoul government has said it could reconsider it if Japan retracts the export curbs.

Milley will take the helm of the US JCS on Oct. 1. (Yonhap)