The Dubsmash Wars began as a friendly competition between Marvel TV stars Chloe Bennet and Clark Gregg from "Agents of S.H.I.E.L.D." and Hayley Atwell and James D'Arcy from "Agent Carter" at the 2015 San Diego Comic-Con. It has now led to an ultimate showdown between Team Carter and Team S.H.I.E.L.D. to create the best Dubsmash video and to support two worthy charities.

"Recently James and I got into a musical tussle with some very dear friends," Atwell said in the video announcement for the upcoming "Dubsmash Wars for Charity." "But to our surprise," D'Arcy joined in before handing it back over to Atwell, "that innocent Comic-Con skirmish took on a life of its own."

Atwell, D'Arcy, Bennet and Gregg all came together on Friday for the video announcing the next round of "Dubsmash Wars" that will kick off Wednesday, Sept. 2. Through the fundraising website CrowdRise, fans serve as judges for the three-round competition and will donate one dollar for every vote they cast.

All the money collected will go to two charities, either Stomp Out Bullying or St. Jude Children's Research Hospital. Every vote by dollar also gives fans the chance to win a trip for two to Hollywood to have lunch with the Marvel TV stars and create a Dubsmash video altogether.

Team S.H.I.E.L.D. will drop its first round video on Sept. 2 followed by Team Carter on Sept. 9.

The Dubsmash app allows users to lip-sync their favorite songs or quotes in short, 10-second videos. Gregg and Bennet started things off with their versions of "It Takes Two" by Rob Base and DJ EZ Rock followed by Rihanna's "B---h Better Have My Money."

Atwell and D'Arcy then dropped the mic and threw it "out of the f***ing window" when they recruited Captain America himself, Chris Evans, to join them in videos "singing" Queen's "Another One Bites the Dust" and "(I've Had) The Time of My Life."

Gregg told Zap2It that he may call in friend or two from the Marvel universe, but dubs himself a "Dubsmash purist."

"I don't think they call it 'Celebrity Cameo-Smash.' I may reach out to some friends, but at the end of the day, do you want to play 'Love Boat' or do you want to play 'Dubsmash,'" he said.

Return to HNGN for more updates on the epic Dubsmash Wars.