Timothée Chalamet Skips Met Gala to Watch New York Knicks Playoff Game

Timothée Chalamet had a pretty good reason to let Kylie Jenner fly solo at the Met Gala ... his NBA team was playing an important playoff game, and he had to watch!!!

The actor, who is a big Knicks fan, was nowhere to be found at Monday's Met Gala in New York City ... instead, he was tuning in to watch the Knicks play the Boston Celtics in Game 1 of their series.

Timothée may have made the right call here ... the Knicks won in thrilling fashion, storming back from a 20-point deficit to shock the defending-champion Celtics in overtime, 108-105, to steal home court advantage in the best-of-7 series.

The game was tense, and so were Timothée's nerves ... he posted "s****ing myself this game is insane" and "shaking What a win."

Timothée and Kylie were making out courtside at a Lakers playoff game last week in Los Angeles ... the Lakers lost that game, so maybe it's a good thing the Knicks were playing in Boston and Timothée was cheering from the couch.

As for Kylie, she wouldn't miss the Met Gala for an NBA game ... and she looked stunning as usual.

The Knicks host the Celtics in Games 3 and 4 on Saturday and Monday at Madison Square Garden ... and it will be interesting to see if Timothée and Kylie are in the house.