Olly Murs suddenly grew a set of abs!

Feast your eyes on the evidence: A before-and-after shirtless selfie posted by the pop star's trainer Rob Solly:

Murs, the 31-year-old former X-Factor runner-up you probably know from his hit songs "Troublemaker" and "Wrapped Up," has been getting swole with Solly for the last 12 weeks in preparation for his Never Been Better Tour supporting his fourth studio album by the same name.

Rob wrote: "This is what happened to @ollymurs when we had 12 weeks training to get tour ready ?"

Murs has been documenting his progress with workout videos and diet shots on Instagram for the past few months. We're glad to see his hard work paid off! ???

Looks like the abs came just in time for Olly's 2016 calendar, too. Check out that hot topless photo right there!