Conversation so far:
When was the song Oppa Oppa released?
The digital single Oppa, Oppa was released on 16 December 2011.
Who did Eunhyuk release the song Oppa, Oppa with?
Eunhyuk and Donghae released digital single Oppa, Oppa.

Question: When did he perform with super junior?
Self-contained rewrite: When did Eunhyuk perform with Super Junior?