If you attended this weekend's Evolution Champion Series (EVO), an annual e-sports event focused on fighting games, and you saw Street Fighter's Vega hanging out with Tekken's Doctor Bosconovitch, then there's a fairly good chance that was actually Jamie Lee Curtis (A Fish Called Wanda, True Lies) and husband Christopher Guest (Best in Show, This is Spinal Tap) cosplaying at the event.
Turns out, as Polygon notes, that Jamie Lee Curtis is a fighting game fan. It also turns out, as we choose to believe, that Jamie Lee Curtis has been playing Vega since the character's debut in 1991's Street Fighter II (known as Balrog in Japan).
Here's all of Jamie Lee Curtis' Super Street Fighter II Turbo special moves.
Guess who showed to @evo2k? Jamie Lee Curtis, that's who! pic.twitter.com/UuC95GwlJf
— Joey Cuellar (@EvilMrWizard) July 18, 2015
Rainbow Suplex
When close, press back or forward + Medium Punch or High Punch
Jamie Lee Curtis walks up to the opponent with her arms outstretched, asking why we fight at all — I mean, what's the point really? The money isn't enough to sustain a healthy lifestyle, our skill sets would qualify us for better-paying, lower-risk employment, and besides, there's only maybe three people watching from across the fence. Jamie Lee Curtis then offers the opponent a hug, before revealing this to be a true lie, grabbing the opponent with superhuman JLC strength, and throwing the opponent over her shoulder.

Rolling Crystal Flash
Hold back, then press forward + Low, Medium, or High Punch
Jamie Lee Curtis backs up a few steps, motioning with her claw hand that the opponent has something on his or her nose. When the opponent, appreciative of the concern and embarrassed about the presumed out-facing booger, reaches up to check on his or her news, Jamie Lee Curtis reveals this to be a true lie, launching herself toward the opponent with a powerful forward role.

Sky High Claw
Hold down, then press up + Low, Medium, or High Punch
Jamie Lee Curtis fools her opponent into thinking she's tying her shoe before revealing that to be a true lie, jumping toward a wall, and then launching head-and-claw first into the opponent.
Grad trip to @evo2k. 2 stay incognito was Vega who wears a mask. @StreetFighter family. DJ, Dr. Bosconovich, Makoto. pic.twitter.com/b3wOgxPgAG
— Jamie Lee Curtis (@jamieleecurtis) July 18, 2015
Flying Barcelona Attack
Hold down, then press up + Low, Medium, or High Kick, then press punch
Jamie Lee Curtis jumps toward a nearby wall, fooling the opponent into thinking she's about to do a sky high claw, before revealing it to be a true lie, letting out a fierce (albeit high-pitched) battle cry, and dive-bombing the opponent with her arms (and claw) outstretched.

Izuna Drop
Hold down, then press up + Low, Medium, or High Kick, then press left or right + Low, Medium, or High Punch
Jamie Lee Curtis jumps toward a nearby wall, exhausting the opponent into wondering aloud, "okay, what is Jamie Lee Curtis going to do this time around?" The opponent prepares for some claw-based attack before Jamie Lee Curtis reveals that to be a true lie, grabbing the opponent at the last minute, and performing some kind of mid-air suplex. This typically breaks the opponent's neck, based on the relative point of impact with the ground.

Scarlet Terror
Hold diagonally down-and-to-the-back, then press forward + Low, Medium, or High Kick
Jamie Lee Curtis bends down as if to tie her shoe. The opponent screams "C'mon! Seriously! You tried this already and you have no shoe laces!" Jamie Lee Curtis says, "No, seriously, I think I've lost my contact lens, can you please help me find it?" The opponent, charmed by Jamie Lee Curtis' affable and charming demeanor, both figuratively and physically lets his or her guard down and walks over looking for the missing contact lens so that the fight can continue. At that point, Jamie Lee Curtis reveals the ruse to be a true lie, back-flipping into the air and kicking the opponent with her lace-free shoes.

SUPER: Rolling Izuna Drop
Hold diagonally down-and-to-the-back, then roll the joystick in a half circle from forward to down to back, then press diagonally up-and-to-the-front + Low, Medium, or High Kick, then when close, press back or forward + Low, Medium, or High Punch
"The only true lie today was you thinking you could defeat me!"
Jamie Lee Curtis drops to one knee but makes no attempt to fool the opponent into looking for a contact lens or tying a shoe with no laces. "To call you stupid would be an insult to stupid people!" she screams. "I've known sheep that could outwit you. I've worn dresses with higher IQs!" The opponent keeps his or her distance. Jamie Lee Curtis growls, "the only true lie today was you thinking you could defeat me" before jumping towards a nearby wall and hurling herself towards the opponent with the strength of a Harrier Jet. "JAMIE LEE CURTIS SMASH!!!!!!!!" she bellows as she seems to magically grab the opponent from behind (despite launching from the front), holding onto the opponent while shadows of all her past characters join in to perform not one, not two, but three sequential suplexes.
"And they said I'd never do a trilogy," she quips, standing over an opponent whose life has long escaped.

NEXT TIME: All of Christopher-Guest-as-Doctor-Bosconovitch's Tekken moves
All screencaps via this YouTube video of Jamie Lee Curtis c. 1994