Viewers watched the dramatic showdown between Katie and her brother-in-law Robert Sugden, in which she fell to her death after Robert threw her across some unsafe floorboards at Wylie's Farm.
In Katie's final scene, her husband Andy Sugden (played by Kelvin Fletcher) was left distraught after finding her dead at the farm.
In a video posted on Emmerdale's official website last night, Sammy took fans behind the scenes of Katie's dramatic exit and revealed she was pleased to have her final scene with Kelvin.
"I hope that this storyline does the character justice after 13 years," she said. "I think it will really show the relationship between Katie and Robert and Katie and Andy."
Kelvin praised his co-star, saying: "It's a farewell, I'm pretty emotional myself. I've worked with Sammy now for over 13 years. It's been unforgettable. She's a terrific actress and human being and I wish her all the best."
After her final scene, Sammy was given a large bouquet of flowers by Kelvin, and she thanked the cast and crew before breaking down in tears.
Sammy joined Emmerdale in 2001. Speaking about her exit in a recent interview, she said: "I'm going to miss everyone terribly. I've loved every second of playing Katie but no one becomes an actor to play just one role, so now it's time for me to move on."
Emmerdale airs weekdays at 7pm on ITV.
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