She said she didn't know she was being recorded when she outright told the crowd she was running.
"I'm going to do it, I'm going to rise up and lead the state," Tupola said in the video. "It won't be my tenure for eight years as governor, it will be yours. It will be us working for eight years together for a better Hawaii."
So far she's held two rallies on Oahu and plans to host more rallies on Maui next week.
Tupola is one of five Republicans in the 51-member state House. She was first elected in 2014 and is the House minority leader.
Hawaii News Now interviewed Tupola and asked for confirmation on Tuesday.
She admitted she's grooming another woman to take over her seat next year and she's raising money for her own campaign for governor, but she hasn't signed any papers yet.
"I want to make sure our team feels ready to do this," Tupola told Hawaii News Now. "We have a fundraising threshold we're trying to hit and a volunteer threshold so that once we launch, it's not overwhelming and we have enough support an resources to handle what's going to come at us."
Tupola rose to prominence quickly in the last year.
In February, Tupola was chosen to replace Beth Fukumoto as House minority leader.
Then in August, Tupola emerged as the top GOP candidate for Governor after Rep. Bob McDermott of Ewa Beach withdrew his name from the 2018 Governor's race.
On the democratic side, incumbent Governor David Ige will be facing formidable challenger U.s. Rep. Colleen Hanabusa.