Genre: Unsure

I've searched these tags:
Acting
Actor/s
Actress/es
Appearance Different from Personality

Yet to check:
Shy Male Lead
Glasses Wearing Protagonist

Genres:
Romance? Drama? Shoujo?

I'm falling asleep atm but I recall some time ago reading this story about this former (unsuccessful) child actor who failed to get past auditions while his childhood friends (guy and girl) did.

They convince him to read as a stand in for something and when he does he blows everyone away with his performance. They urge him to become an actual actor but he declines for personal reasons...until his male childhood friend taunts him about stealing their female friend away.

I recall reading it on mangapark some time ago (like 2/3 years) and for some reason it was accidentally uploaded as a one shot. Not sure if it was ever fixed but yeah.

Protag has black hair and glasses. Girl has long hair. Other guy is taller than both of them. The girl flirts with him and the guy returns the favor but I think one of them gets embarrassed by their lack of chemistry or something.

I found Be Mine in the Child Actor/Actress tag so maybe that? It's the only one without a description, the others in the tag didn't seem to match yours (in that the main characters were female).

Must Read Webcomic:
Unsounded

Lists:
Reading
Complete
Western Webcomics

Trio: 2 boys and a girl. All child hood friends.

Girl was your typical cutsy energetic go getter. MC was a dork who kind of hid his acting ability back for some reason. The other guy is the type to challenge MC and tease him by trying to do physical stuff to their female friend.

Just checked out Be Mine and its not it unfortunately. Seeing how that it was a incorrect one shot, I am checking that tag now.

http://mangapark.me/manga/rain
Example of how they uploaded a one shot incorrectly. Just check the comments lol.

How about Torch Song Ecology? The main character wears glasses. It doesn't seem to totally fit, but I think it's similar enough that it's a possibility.

(Your description seemed so interesting that now I'm trying to look for it to read for myself.)

Edit: Or maybe it's: Ano Ko no, Toriko.?

Must Read Webcomic:
Unsounded

Lists:
Reading
Complete
Western Webcomics

Quote from mikako17

Edit: Or maybe it's: Ano Ko no, Toriko.?

YES! This is it!