While attending a retreat for families with blind children with Kate (Toby stayed home while their marital woes deepened), Rebecca decided they should go for a swim at night, which didn't sit well with her daughter. That didn't deter her mom, though.
"You're fat, I'm ancient. We’re gorgeous," Rebecca declared in a sweet moment of empowerment.
The line struck a chord with fans.
"One of my favorite #ThisIsUs quotes ever!" wrote one person on Twitter.
"We all got something but can’t let it define us!!" someone else wrote.
"Perhaps the best line ever written. If you wait until you are good enough, it will simply never happen," another person commented.
"The diagnosis has made me feel more powerful. I'm more fun," she said. "'Cause I'm not sweating the small stuff. I don't know how much longer I have before things might get worse. I'm done being sad and I'm done feeling worried. I feel, feel OK."
Her vitality and attitude certainly had an impact on Kate.
"I'm strong. You made me strong," she told Rebecca before they hugged.
They would continue bonding even more when they performed a karaoke version of Alanis Morisette’s “Ironic.”
We even learned that Rebecca coined the nickname "Bug" for Kate because she loved bugs — especially lightning bugs — as a little girl.
While the episode centered on teenage Kate’s destructive and abusive relationship with first boyfriend Marc and her crumbling marriage to Toby, the heartwarming interactions with Rebecca presented a nice change of pace, considering she had always seemed to have more of a connection with her father than her mother.
"BEAUTIFUL moments between mom & daughter..I'm loving it...," one fan commented on Twitter.