The actress told Corden on Monday that her casting as Ahsoka started from a drawing done by artist BossLogic.
The artwork gained the attention of fans and Mandalorian executive producer Dave Filoni, which led to Dawson portraying Ahsoka.
"There was an image made of me as this character years ago. BossLogic had sent to me I believe a couple years ago, me as this character. I replied back on Twitter and then that got to Dave Filoni who then kind of compartmentalized it for a little while until this show came up," Dawson said.
Dawson also showed the unique plush doll her boyfriend Sen. Cory Booker gifted her for Christmas, which resembles Booker.
"Did your boyfriend, girlfriend out there decide to make you a little version of themselves to spend the holidays with? Because mine did," Dawson said while holding up the doll and laughing.