T.O.P
T.O.P is probably the best k-pop actor. His acting talent was noticed early in his career in the various music videos he starred in. A few of my favourites are BigBang's "HaruHaru", Gummy's "Sorry", and Red Roc's "Hello". He then went on to star in 'IRIS' and 'Nineteen'. The film that really got people's attention, though, was '71 Into the Fire' which is based on the 71 teenage soldiers who protected the P'ohang-dong girls' middle school during the Korean War. T.O.P has another movie coming out called 'Alumni' which looks promising. He plays a North Korean spy whose sister has been kidnapped. There's going to be action and drama and from what we've seen in his previous projects, I'm positive he'll do a good job.
Lee Joon
MBLAQ's heartthrob, Lee Joon, usually plays the main character in the group's music videos such as "Y" and "This Is War" where he plays more serious characters. If you're in the mood for a cute and goofy Lee Joon, check out K. Will's "My Heart Is Beating". He got his big role in the American movie "Ninja Assassin" where he plays the younger version of Rain's (MBLAQ's mentor) character. I think G.O looks more like Rain but Lee Joon definitely showed off his acting chops so I wasn't complaining. The movie wasn't that amazing but Lee Joon did a great job considering what he had to work with. He then went on to star in his first K-Drama "IRIS 2" which I haven't seen yet but it's on the list.
HongKi
Jeremy! 'You're Beautiful' was my first K-Drama and Jeremy is one of my favourite characters ever. I love how he chooses to be happy all the time and chooses to look on the brighter side of things. I thought HongKi did a fantastic job especially during that heartbreaking bus scene which really showed off his talents. He always does a good job in FT Island's music videos and 'Rockin' On Heaven's Door' looks like it will be good. I've been trying to watch it online but I can't find it. Sad panda.
Hoya
I never payed much attention to Hoya when watching Infinite music videos. He was just the guy who looks like Yunho. I thought he was cute in Infinite H's music video for 'Special Girl' but I still didn't really get what the big fuss was about until recently when I watched 'Reply 1997'. That drama is probably in my Top 5 and Hoya's character was one of my favourites. I thought he was perfect for the role and I was very impressed.
L
It took me a while to warm up to L's character in 'Shut Up Flower Boy Band' (I think it just took me a while to warm up to Infinite in general) but I don't think it had anything to do with L's acting. I expected his character to be more like the maknae and use aegyo all the time because of the way he looks but that doesn't suit him at all. He's very good at acting tough and cold but then he smiles and he's like the sun. His acting is improving with every project. I just started watching 'Master's Sun' and he's doing a wonderful job.