Harry Styles may not be known for his muscular physique but we he will soon.

Just last week, Styles was out and about in sunny Los Angeles without a shirt on. Judging by his skinny frame before, it looked like the teen superstar singer has been hitting the gym.

The One Direction singer revealed that he has been doing grueling workouts in the gym to tone his torso and arms. Styles was seen with a buffer and more muscled frame recently and even donning a few more tattoos.

The singer was also seen out walking a pal's black Labrador while shirtless sporting a pair of white Nike shorts and wearing a baseball cap backwards. The singer posted photos of his skinny upper body, and now, in a matter of 5 months, he gained a lot of muscle and built it fairly well.

The band's career started in 2010 that soon made way to stardom. Styles was a skinny fellow back then without any tattoos. Now, he and a fellow band mate were in a competition to have the most ink.

The band consists of Zayn Malik, Harry Styles, Niall Horan, Louis Tomlinson and Liam Payne. They recently came from a tour and sold out concerts at the Staples center. One Direction recently bagged four awards at the Teen Choice Awards and Harry got two solo awards, one for Top Hottie.

Well, he certainly is turning into a hottie by the minute, and most of his fans cannot wait to see how much more muscle he will be putting on after his work outs. Zayn Malik also got pretty buff, as he showcased his newest tattoo of his girlfriend's face on his arm - this must have gotten the ladies screaming.

Malik and Styles were known to be competing with each other on the number of body art and ink they had done since they first started getting tattoos.

The boy band just came from a tour where they had sold out concerts and had performed at the Staples Center.

Catch Styles, Malik and the rest of the boys of One Direction as they release their documentary "This is Us."