U.S. President Barack Obama, South Korean President Lee Myung-bak, Chinese Premier Wen Jiabao and Japanese Prime Minister Yoshihiko Noda have already confirmed their participation in the 21st ASEAN Summit and related Summits here on Nov. 15-20, said Cambodia's Foreign Minister Hor Namhong on Monday.

"All heads of states and governments of the member states of the Association of Southeast Asian Nations (ASEAN), President of South Korea, President of the U.S., Chinese Premier and Japanese Prime Minister will come to join the Summit," he told reporters after a meeting with visiting Indonesian Foreign Minister Marty Natalegawa.

He said that in the meeting with Marty, both sides discussed the preparation for the 21st ASEAN Summit here next month besides talks on bilateral relation boost.

Founded in 1967, ASEAN groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam.