Matthew Lewis, who caused a frenzy when photos of his buff,

new look surfaced on Twitter, is going one step further to show off his recent

transformation. In the new issue of the British gay magazine, Attitude, the actor strips down to his

skivvies to give fans a full view of his six pack -- and more.

Attitude Magazine

Though, the new bod doesn’t come without effort. The 25-year-old

actor explains that he gave up alcohol in order to portray a triathlete in the

new film, Me Before You, co-starring

Emilia Clarke (Game of Thrones) and Sam Claflin (The Hunger Games series).

“I spoke to the director and I said it’d be nice

to get into the mindset of someone like that, because he’s not drinking

alcohol, he’s just eating salads all the time, and I was very interested to

know where you go to in your mind to have that level of commitment,” Lewis says.

“So I sort of gave up alcohol -- I say sort of, I have given up alcohol.”

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He also reveals that his diet has taken a hit.

“I’m off sugar and I can’t really eat carbs. I really wanted

to see if I could stick to such a strict regime, and to really understand what

it’s like to have a goal like that and really 110 percent go for it,” Lewis

says. “I mean I’ve always been a bit of a sports enthusiast anyway, I love the

gym and all that stuff, but I can’t wait for a pint of lager, I tell you that!

The pizza and beer will definitely be making a comeback over the summer.”

Attitude Magazine

Well, Potter fans rejoice because the hard work has paid

off! And it even caught the attention of author J.K. Rowling, who responded to Lewis' photo shoot on Twitter. "Not as bad as watching Dan in Equus, but close. Warn me next time, for God's sake," she joked, making reference to Daniel Radcliffe's nude performance in the Broadway play.

Needless to say, it was a little awkward for the former Potter star.

.@Mattdavelewis I will always support you whatever you want to do, Matthew. Now go put some clothes on. — J.K. Rowling (@jk_rowling) May 21, 2015

In case you missed all the excitement surrounding Lewis earlier this year, watch the video below: