global news anchor katie couric 26-year-old internet mega star pewdpie for our series, social stars. >> reporter: adel's latest album may be breaking records but when it comes to the world of youtube, adele, taylor swift and beyonce combined can't top this guy's numbers. >> they call him pewdiepie. famous for recording himself playing video games. >> oh, my god. what the [ bleep ]. i can't find the blooes now? pewdiepie? >> any gamer, i guess, will have a nickname. i would nick pew like the lasers, pew pew. and i would yell out pewdiepie whenever i did well in games and people would laugh. i went with it. >> they told me i could become >> reporter: his real name felix kjellberg, currently has the most popular channel on youtube with over 40 million subscribers. his videos now seen over 10 billion times. when the numbers started to climb though, i mean, it must have been a little mind blowing for you. was it? >> i never expected it. i never been the popular guy or whatever. to all of a sudden be in this situation where there's so many people who loves what you do and appreciates what

." >> do you think at some point you will be too old to be pewdpie? >> yeah, ridiculous. like i'm 70 and i'm just sitting there playing games. commentating like i am now. i feel like already in these five years my content has evolved a lot and i think it will keep evolving. >> do you see yourself continuing to do this or do you want to use this as a springboard for other opportunities? >> it's true. a lot of people do want to use youtube as springboard. passion for gaming. that's what i want to keep doing. >> making me so anxious. >> reporter: for "nightline," i'm katie couric in new york. >> as they say, stay tuned. for katie's full interview go to yahoo!.com/katiecouric. >>> up next, the hottest gadget trend this gift giving season. could conrns over safety? >>> abc "nightline" brought to you by pfizer. i re had a lot on my mind when i got out of the hospital after a dvt blood clot. what about my family? my li'l buddy? and what if this happened again? i was given warfarin in the hospital but i wondered if thisas the right treatment for me. then my doctor told me about e