Does countering a spell negate Irelia - Fervent's ability from activating when she was chosen as the target?

Ruling: Irelia's ability triggers when she is chosen during spell finalization, which occurs before the opponent can counter the spell. Therefore, even if the spell is countered, Irelia's trigger has already been placed on the chain and will resolve.

Sequence:

• Spell is finalized and Irelia is chosen as the target
• Irelia's ability triggers and goes on the chain
• Opponent can now counter the original spell
• Even if countered, Irelia's trigger remains on the chain and resolves

Nuances:

• This same principle applies to other "when chosen" effects like Dreaming Tree
• Attaching gear also counts as choosing the unit with that gear, triggering Irelia's ability before the gear actually attaches