It is not commonplace for government officials to attend any central bank meeting, so this is definitely a peculiar one. But I guess it speaks to the delicate situation regarding the Japanese yen at the moment. The last time this happened was back in December last year, and before that was all the way back in April 2020 during the pandemic.
If there is no firm pushback by Ueda tomorrow, traders might take that as a green light to sell the yen further. USD/JPY is relatively unfazed by the headline for now, staying underpinned at 155.60 currently.