The A-list actor was among the many celebs who made a big splashy entrance at the Beverly Hilton Sunday ... but he was without a date on his arm, and handled the arrival all on his own with no sign of Kylie whatsoever.

Fortunately for all of us, the seating arrangement photos were already making the rounds this weekend ... and Tim's name card was right next to KJ, at a table with J-Law no less.

Unclear why Kylie didn't just roll up with Timmy ... but he collected her once the show got rolling. According to reporters in the room, TC and Kylie entered the ballroom together at some point after the first break ... and they went to their seats and looked lovey-dovey.

There are countless clips of BTS cameras that are capturing all the action that the main telecast isn't showing ... and you can see Kylie digging Tim's stylish duds/jewlery.

The homeboy himself was looking deep into her eyes as they chatted, and he eventually planted a quick kiss on her in front of everyone -- or at least whoever was paying attention.

At some point, the cat was fully out of the bag ... as it appears they showed up on the main broadcast as the rest of the presenters did their thing on stage -- with a camera panning to them and Tim/Kylie smiling wide. If they were trying to lay low, this wasn't the place for it.

Hard to say if this counts as their official red carpet debut as a couple -- again ... Kylie didn't show up for that somewhat important part. Still, they're claiming each other pretty loudly behind the scenes ... and are clearly going strong several months after first going public.

Maybe as it gets closer to the Oscars -- where Tim will presumably be invited -- they'll just pose together once and for all. At this point, everybody knows they're an item.