Justin Timberlake Stays At Wynn Las Vegas After Performing at Fontainebleau

Justin Timberlake apparently made a boatload of $$$ for his performance during the grand opening of the Fontainebleau Hotel in Vegas Wednesday, but he triggered a hotel war by staying overnight at the Wynn.

Justin shared a pic after his big appearance at Fontainebleau's big event, strolling down a hotel hallway with his wife, Jessica Biel. Thing is ... something looked off.

Social media sleuths noticed the hallway isn't part of the Fontainebleau ... it's the Wynn! So dude got a reported $6.1 million from the Fontainebleau and chose to put his head on a Wynn pillow.

The folks over at Wynn found JT's post irresistible ... re-posting the pic on the hotel's IG with the caption, "where everyone ends up."

Wynn's post has been taken down, but point well made!

We checked with Fontainebleau and although rooms Wednesday night were not available to the public, they were available to the celebs, including Justin, who attended the grand opening.

The feud between Fontainebleau and Wynn has been brewing for a while. Wynn had accused Fontainebleau of poaching its employees, so this was payback.