Blake Lively may have shocked some when she stepped on the Met Gala red carpet last night … but the actress being there wasn’t a last-minute decision.

A Blake insider tells TMZ … despite her attendance at the Gala turning heads since earlier in the day, her massive legal battle with Justin Baldoni was finally settled … her presence had been planned for weeks, as she was an invited guest by Anna Wintour.

We’re told … the 11th-hour settlement was irrelevant — BL was going to the Met — no matter if there was a settlement, or the trial was still on the horizon.

We broke the news — Justin and Blake agreed to a settlement Monday morning — but we’ve since learned from sources that no money was exchanged between the parties … other than the lawyers getting paid, of course.

As for hubby Ryan Reynolds skipping the gala, our insider says … RR does not always go to the bash, and the couple often attends events separately. Plus, other A-listers went stag, like Katy Perry without Justin Trudeau, and Kylie Jenner sans Timothée — who was at the Knicks game. We hear Ryan was home spending time with the kids … having been away recently for screenings of his John Candy doc, “I Like Me.”

Asked how she was feeling about the evening, Blake told Vogue on the carpet … “Every year I am a different version of myself than the last, so to be able to stand here in the version of myself that I am today — and all the experiences I’ve had — and strength and confidence is important to me.“