There’s something weird about ZZ Top. Not in any musical or malevolent way, as a terrifically entertaining show last night at a sold out Queen Elizabeth Theatre proved. It’s just that guitarist Billy Gibbons and bassist Dusty Hill, hiding behind giant beards for the best part of 40 years, don’t appear to have aged a day. Drummer Frank Beard (as every pop trivialist knows, the only member of ZZ Top who doesn’t have a beard) has hardly changed since the band’s mid-’80s heyday either.

Maybe the Texas trio have been using Oil of Olay judiciously all along. But it’s likely the secret to their eternal youth is something far more elemental. ZZ Top are perhaps America’s greatest stripped-down, meat ’n potatoes blues-rock bands. The music never ages. Neither do the men that play it. Or so it would seem.

Celebrating the 31st anniversary of the release of their greatest album, “Eliminator,” a day early, the boogie-woogie warlocks opened their set with “Got Me Under Pressure.” “Gimme All Your Lovin,’” three songs later, prised the crowd out of the comfort of their royally approved theatre seats.

Check out the beard-filled photo gallery

Having been on the road since before the Vancouver Canucks existed, Gibbons knows how to charm a crowd, revelling in an anecdote about the novelty of taking a ferry to Victoria and back again. Although if the ship’s captain really does let retirement age rockers take the helm, even for a short stint, passengers should be grateful it wasn’t Ozzy Osbourne behind the wheel.

“We’ve been doing this for four decades,” smiled Gibbons from behind his ever-present shades at the story’s end. “Same three guys. Same three chords.” The perfect introduction to desert rock classic, “I’m Bad, I’m Nationwide.”

The hits and deep cuts continued via prehistoric (“Jesus Just Left Chicago”) and 20-year old tunes (“Pincushion”), all the way up to the present day (“I Gotsta Get Paid”). Playing without a single guitar pedal on stage, the sonic palette remained so steady the only way to separate the eras was from the haircuts and outfits on the models in the videos on the giant screens behind the band.

That was no bad thing. Fiery enough to still rock through “Cheap Sunglasses,” chilled enough to pass around and sign a fan’s “Tres Hombres” LP between songs, and quick enough to jokingly pretend to auction the disc off before returning it to its rightful owner, the ZZ Top formula continues to defy father time with wit and without compromise.

The big finish of “Sharp Dressed Man” was followed by a change of jackets and a horndog encore of “La Grange” and “Tush,” both full of choreographed moves so daft-yet-loveable it’s a mystery why every guitar band hasn’t ripped them off.

In a world full of uncertainty, it’s good to know that some things never change. ZZ Top’s unwavering commitment to rock, riffs and beards has transcended musical and facial hair fashions. Timeless stuff indeed.