Gives new meaning to three-piece suit. Photo: Getty Images

Sorry to burst your bubble, ladies, but chances are your boyfriend has not been hitting the gym as often as he claims.

Nope -- those firm new pecs and sleeker beer belly may be courtesy of -- brace yourself -- a man corset.

British online retailer reports that men's shapewear -- including slimming corset-like tops and, um, body-enhancing undies -- has been a huge hit since the site introduced it in May, comprising 10 percent of their men's underwear sales, ITN reports.

(The good news? You can now stop darting to the bathroom to secretly remove your Spanx.)

"Since May, it's come from nowhere really," Figleaves Senior Buying Manager Zoe Ellis told ITN. "I think men are looking after their bodies a lot more."

According to the source, the shapewear first won fans among gay men, but its popularity has spread to straight men wanting to look lean and mean.

Let's just hope they don't know about "mantihose."

Think men's shapewear is weird? Check out this left-handed underwear.