The Emmy-nominated actress plays Pearson family matriarch Rebecca on the hit NBC drama, and she teased story details most fans probably already picked up from watching the first trailer that went online earlier this month.
"The Jack and Rebecca courtship is what gets explored for the first half of the season, so it's fun. I feel like i get to smile and laugh and enjoy myself -- I cried all of the tears humanly possible last season," she explained. "I will still do present day and we're also of course juxtaposing the sort of love-sick courtship days of Jack and Rebecca with the time period right after Jack passed away."
"This Is Us" is the latest tearjerker for the actress, who rose to fame as a teenager when she starred in another memorable drama, "A Walk to Remember." Fallon read her lines of dialogue and challenged his guest to identify if it came from that beloved 2002 teen drama or "This Is Us," and she crushed it.
While Fallon was praising his guest for playing a character across the spectrum of ages as the show jumps back and forth in time, she revealed a fun fact: laughter and tears are bad for prosthetics.
"It's tough because Sterling [K. Brown] and Justin [Hartley] and Chris Sullivan, they're all such jokesters," she explained. "They're all laughing and I'm not supposed to move in my prosthetics too much. The more you move and talk and laugh, it loosens them up."
"And we realized very early on in the show tears are sort of the perfect solvent for removing the prosthetics," she continued. "My face would start melting halfway through the day, and they're trying to spackle me together to keep me going."
Fallon had another game up his sleeve for his guest, too. They played one of his recurring games, The Singing Whisper Challenge, and the late-night host said they set a record, nailing three of four songs they had to identify simply by lip reading while wearing noise-cancelling headphones.