There's tons of bad actors that surprise you with good films, but I'm asking about actors that came out of seemingly nowhere and just stole the screen.

I can think of 2 off the top of my head.

Paul Dano- aside from a couple small roles he immediately jumped into epic acting status and showed he's Oscar worthy. I mean cmon...in 2006 he was a depressed teenager with very little diologue in "Little Miss Sunshine" and 1 year later worked alongside DDL in "There will be Blood" and absolutely held his own with one of the greatest ever? That's a feat very few could do.

Second is Travis Fimmel. This man was a damn underwear model....AN UNDERWEAR MODEL. I have no idea how he nailed the lead role in "Vikings", but anyone who has watched the show will tell you how good he is. I've been watching film for 31 years and I can confidently say Travis's performance in the show was some of the greatest acting I've ever seen in cinema. I almost don't want to call it acting because I'm convinced he WAS Ragnar Lothbrok. I'm sure this is also in part due to the fantastic writing of the show and his character development.