There have been few Fringe comedy debuts quite like Bo Burnham’s. Back in 2010, he was widely known as the kid who performed silly songs in his bedroom to virtually patent the term ‘internet sensation’. For those who awaited his arrival in August of that year as a chance to shoot down this young pretender, Words Words Words left most onlookers speechless. One rave review after another greeted his very literate, very musical, and extremely funny hour which had him tearing up newspapers and ripping a hole in the theory that originality and wit are mutually exclusive entities.

Burnham’s spectacles don’t need to be tinted with rose for him to look back on that month with extreme fondness. ‘I had no idea that was coming,’ he insists of the overwhelmingly positive reaction to his run. ‘That would be sociopathic of me to have expected it. I had all these ideas about my stand-up and about my show that I’d been working on for years, and I had never really heard anybody articulating it back to me; so I didn’t know if I was doing it right or not. Sometimes in the US, comedy isn’t examined in the way it is in the UK, and I was blown away that people would be looking so closely at my ideas. I am hugely flattered and intimidated to be going back, but I’ve spent three years making a show that can only be disappointing. And I’m probably playing a room that is slightly too big, so I’m setting myself up for a colossal failure.’

Immediately after his 2010 Fringe glory (the judges somehow failed to adorn Burnham with the main Edinburgh Comedy Award, but instead handed him the consolation ‘panel prize’), and having just left his teenage years behind, he resumed a working relationship with Hollywood’s comedy-film behemoth, Judd Apatow. Those sessions turned out to be a profitable experience which helped Burnham grow as a writer rather than a collaboration yielding a concrete project.

‘I learned something so valuable which was how to write a script from one of the best writers around,’ Burnham concludes. ‘That was a huge gift. I’ve been working on scripts since then and if they have any qualities, they come directly from the input he has given me. He sat across from me when I was a 17-year-old and talked to me like an adult and gave me respect and listened to my opinions. He treated me like an equal when he really shouldn’t have.’

Burnham credits that time as being hugely beneficial towards his first venture into the world of TV comedy, the mockumentary sitcom Zach Stone is Gonna Be Famous. As star and co-creator of the MTV show about a young man whose only talent is an unquenchable drive to achieve celebrity, Burnham inadvertently plundered those videos he uploaded from his bedroom merely to make friends and family laugh but which were then viewed by millions. ‘Looking back on myself then is terrifying, and I thought I had abandoned every persona I’d taken on for those YouTube videos. I was way too enthusiastic and such a ham. But in making Zach Stone, I think I tapped into this older version of myself and criticised it through the show. But even though I’m critical of it, any element taken out might not have given me the opportunities I have now. I’m grateful for every stupid mistake and dumb joke I tried to make.’

While he was achieving the goal of getting his first TV project off the ground, Burnham was busy writing the follow-up to Words Words Words, in preparation for a return to Edinburgh. Early reports of the new hour suggest that it’s a more theatrical piece than his debut and while he had a concept firmly in mind, Burnham knew it wasn’t something he could try out in short bursts on the comedy club circuit. ‘What I’m going for is bombastic introspection,’ he insists. ‘It’s a show that I hope feels intimate in theme, but bigger in presentation. I love Tim Minchin, Bill Bailey and Hans Teeuwen and I’m trying to synthesise elements of theatre into my show a little bit more. I want it to be surprising and rich and fun to watch, and maybe a little confusing. It’ll be very loud and very quiet and very sad and very happy, with things that have you leaving the theatre going, “what … “And not “what” with a question mark; just “what”, period.’

A younger Bo Burnham once stated in an interview that ‘not enough comedy makes you feel something’. He tuts like a showbusiness veteran reflecting on the raw naivety of his own youth at such rash pronouncements. ‘That sounds a lot like a 19-year-old kid who thinks he knows a lot of shit. But I do think the rules of comedy generally limit its ability to be more theatrical or emotional. And yes, I would like people to feel something, but maybe my problem is calling it comedy. It just puts it straight into a box and while this show is hopefully funny, there will be parts you can point to and say, “technically, is this comedy?”’

Burnham is able to look back on that dazzling Edinburgh debut with a critical, distanced eye, and can reassure us that he fully intends to go one step beyond it this year. ‘Last time in Edinburgh, I was talking from a very certain place of being 19 and thinking I knew how comedy should be. This hour is much more from a healthy confusion and an acknowledgment that I don’t quite know the purpose of comedy. I hope it feels a little more humble than the last one and about wrestling with ideas rather than just stating them. Hopefully, just watching me wrestle with these ideas will make you feel something.’

Bo Burnham: What, Pleasance Courtyard, 556 6550, 9–19 Aug (not 13), 11.15pm, £12–£13.50 (£11–£12.50).