It was the last day of school before the Christmas break when FDNY Lt. David Royael showed up to his girlfriend's kindergarten classroom in Queens to teach a fire safety lesson.

But Royael, of Engine 243 in Brooklyn, also had a more romantic motivation for being there -- all caught on video.  

In a demonstration to the children, Royael had his girlfriend, teacher Natalie Moy, put on his bunker gear, piece by piece, starting with the pants and ending with his gloves. 

The unsuspecting Moy didn't even realize that there was a box inside one of the gloves, but once it had been pulled out she immediately knew what it was: a box for a ring.  

"Will you marry me?" Royael asked her, bending down.  

Clearly surprised, Moy can barely be heard saying yes, her jaw dropping, as the children erupt in cheers and screams. "The boyfriend! The boyfriend!" they chant as he puts the ring from the box on her finger. 

After the initial shock, someone off-camera says to Royael: "That almost didn't work." 

"I can't believe she put on the glove and she didn't realize the box was in there," Royael replies. 

"I did feel something," Moy replies while giggling. "But I thought it was like a small smoke detector or something." 

The FDNY's Lt. Frank Dwyer, who confirmed the details of the story, said the newly engaged couple have been together two years. Moy has been a teacher for 14 years; Royael has between with the FDNY for 13 years.