Helen Mirren, not her accent, takes a hit of helium with Fallon

Helen Mirren and her posh accent hold up -- even on helium.

The “Woman in Gold” star appeared on Monday’s “Tonight Show,” and despite Fallon’s praise of her “elegant” and “classy” demeanor, the English dame showed him that she can also be crass.

It all started when Fallon asked if her accent would sound the same after sucking a bit of helium. Yes, like, from a balloon. He seems to have a thing for playing with iconic voices. Just ask Morgan Freeman.

“I haven’t done this since I was about 11,” the Oscar-winning “Queen” star laughed.

Then Fallon peppered the 69-year-old with various questions, all of which she answered in a lovely, affected chipmunk voice as is wont to happen after a bit of helium inhalation.

But a word of caution: The National Inhalant Prevention Coalition says, “Inhaling helium sounds like fun until someone dies.”

Warnings aside, Mirren egged him on, which made the bit all the better, and told him to give her an award so that she could deliver an acceptance speech in her proper nasally voice.

Watch the video above to see her accept it.

Twitter: @NardineSaad