Bears' Theo Benedet Sports Tiny Swim Briefs, Sings 'God Bless The USA' In Rookie Showcase

Chicago Bears rookie Theo Benedet might be from the North, but the lineman proved he's all about 'Merica now ... stripping down to a tiny pair of swim briefs to give a patriotic rendition of "God Bless the USA" in front of all his teammates!!

The hilarious moment was featured on the first episode of "Hard Knocks: Training Camp with the Chicago Bears" on Tuesday ... with the undrafted Canadian offensive tackle utilizing his performance in the rookie karaoke showcase to express his love for his new home.

Benedet -- who was born in Toronto and raised in Vancouver -- started off shirtless with a pair of sweatpants ... but he quickly showed MUCH more skin, ripping off his trousers to reveal an eagle-themed suit.

The whole team lost it ... but Benedet continued with his croonin' -- even enlisting a teammate to bang a pair of miniature cymbals for a nice touch.

While it was a special moment for Benedet, it turned sour later in the episode ... as it documented the injury he suffered in the Hall of Fame game against the Houston Texans -- leaving his future with the team up in the air.

The HBO cameras also captured top pick Caleb Williams' singing abilities -- or lack, thereof -- with the superstar quarterback making it just one line into John Legend's "Ordinary People" before messing up.