Katy Perry & Justin Trudeau Have Lunch With Japan's Former Prime Minister

It was the meeting of the former prime ministers Thursday when Justin Trudeau and his girlfriend Katy Perry had lunch with Fumio Kishida and his wife Yuko ... as Katy winds down the Japanese leg of her world tour.

Fumio -- who was Prime Minister of Japan from 2021-2024 -- posted pics of the double date along with the caption ... "We met many times during my time as Prime Minister, and we worked together to strengthen bilateral relations, including formulating the Japan-Canada Action Plan when he visited Canada."

Seeing as how the 2 former national leaders were already well-acquainted, it seems safe to say they may have been more excited about meeting Katy. Look at those smiles!

Fumio added that he was "pleased that our friendship continues in this way."

Justin's been spending a lot of time with Katy while she's on the road for her "Lifetimes" tour. Earlier this week, they were snapped getting dinner in Tokyo at a place that also features live sumo wrestling.