Justin And Hailey Bieber Hug Kendall Jenner and Sway During Concert

Kendall Jenner certainly wasn't a third wheel during a recent outing with the Biebers ... 'cause Justin and Hailey made her feel like part of the group by wrapping her up in a threeway embrace.

The trio were spotted at the Dijon show in San Diego Saturday night vibing to the music in a super famous sandwich formation ... Kendall in front, Hailey directly behind her, arms curled around Kendall's stomach.

Justin's in the back holding them all together in one big bear hug ... while all they gently sway to the dulcet tones of Dijon's voice.

The three broke apart in another clip ... and Justin ran his fingers through Hailey's hair -- just Hailey here -- while Kendall sat alongside them. Still, it was clear the three were feeling super connected in their friendship at the show.

Justin, Hailey and Kendall have been friends for years ... regularly going to events together and looking all loved-up in pics -- like this one where the trio wore matching white outfits and hung all over one another.

A photo taken earlier this year of Kendall in a black sports bra talking animatedly with her hands to a confused Justin also made the rounds on social media earlier this year ... and Hailey commented on it by saying KJ's always telling a story her fingers as much as her mouth.