(only on his suit-jacket)
Based on StackExchange user Double AA:
“Rav Yoel Bin Nun famously slit the slides of his suit jacket rov open and attached tzitzit (with techelet) because he wants to be yotzei the mitzvah on his regular beged as is likely the intention of the pasuk. Source: I’ve seen him!”
R’ Yoel Bin Nun founded Gush Emunim shortly after the 1967 war which encouraged Jews to settle lands just conquered. It formally became an organization in 1974 but has since disbanded. He also co-founded Har Etzion. R’ Bin Nun now lives in Haifa.