Kim Kardashian Supports Ariana Grande at ‘Eternal Sunshine’ Tour Stop in L.A.

Kim Kardashian turned a night at Ariana Grande’s "Eternal Sunshine" concert into a viral moment ... showing up to support her ex-boyfriend's ex-fiancée.

The SKIMS founder was seen in the audience alongside former 'American Horror Story' co-star Emma Roberts, with the pair blending into the crowd as Ariana took the stage for a packed performance.

Despite the attempt to keep things low-key, fans quickly noticed Kim, who was also seen alongside Ari's mom Joan, in the venue and began sharing clips online showing her vibing at the show.

Kim also posted her own video from the concert, giving followers a glimpse of the atmosphere as Ariana performed for a sold-out crowd -- singing along to some of Ari's banger hits.

Worth noting ... this isn't the first time Kim and Ariana's paths have closely crossed, as both women dated comedian Pete Davidson.

Ari was most recently linked to 'Wicked' costar Ethan Slater ... but the longtime couple just moved from Oz to Splitsville.

We broke the story ... Ariana and Ethan Slater have been quietly broken up for several months. Sources close to the former couple tell TMZ ... the split is amicable and the two still remain friends and are very supportive of one another. We're told they gave the breakup careful consideration but ultimately decided to end the romantic relationship.