MANILA - Hayley Atwell, best known for her role as Peggy Carter in the first two "Captain America" movies, has cancelled her scheduled appearance at a pop culture convention in Manila, organizers announced Tuesday afternoon.

Atwell was billed as the headine celebrity guest of the second AsiaPOP Comicon (APCC Manila), which also had a similar snafu last year when Hollywood actor Jason Momoa backed out a month before the convention.

A statement confirmed rumors about the cancellation after Atwell was removed from the convention's website, citing that it was because of scheduling conflicts in connection with the actress' upcoming series, "Conviction."

"Much as we wanted to work things out to fulfill the dreams of her many fans in the region to meet her, this development, sadly, was beyond our control. In spite of this, know that APCC Manila strives to bring you no less than the best and latest in pop culture around the world," organizers said. "Stay tuned for future, guaranteed AWESOME announcements this week -- Hollywood headliners included!"

Aside from the "Captain America" films, Atwell, a British-American actress who has been in the industry for more than a decade now, also starred in the television series "Agent Carter," which aired for two seasons on ABC Studios.

APCC Manila will be held at the SMX Convention Center in Pasay City on August 26-28. The current roster of guests include a mix of popular international and local cosplayers, as well as some well-known comic book artists.

Here's the full list of guests.