"I'm gonna miss Idol," she whispered to fellow judge Harry Connick Jr.
Later, addressing the singers directly, J.Lo explained her surprising reaction.
"While you guys were singing 'There's no place I'd rather be,' I got very emotional because you reminded me how much I love this job and how much I'm really gonna miss Idol," she said, her voice wavering. "I love this whole thing and I love what it does for singers, and I love everything about it. It's been a joy for me to sit here and watch this for so many years. Thank you."
As the hopefuls came together in groups for their latest challenge, Lopez opened up about why Hollywood Week holds such a special place in her heart.
"For me to be part of American Idol is and always has been an honor," she began. "Hollywood Week, you see the artists emerge. You see the real performers emerge, you see who can make it in this business. We're here to find a superstar."
Luckily for Lopez, there was plenty of chocolate on hand during the taping to boost those endorphins. Earlier in the episode, a hilarious montage moment focused exclusively on her affinity for the sweet treat -- and her co-judges' affinity for teasing her about it.