As "Kelly", Johnson replaced the recently departed Denise Nickerson, ultimately appearing in over 250 episodes of the show.
Denise Levertov | Ned Nickerson | Denise Duhamel | Denise Richards | Denise LaSalle | Eugene Nickerson | Denise Okuda | Denise Laurel | SP-350 Denise | Nickerson Field | Denise Ho | Denise Crosby | Nickerson Township, Pine County, Minnesota | Nickerson Township | Denise O'Connell | Denise Frossard | Denise Drysdale | Denise DeBartolo York | Denise Schmandt-Besserat | Denise Robins | Denise Quiñones | Denise Norton | Denise Nickerson | Denise Lewis | Denise Garrido | Denise Dresser | Denise Cote | Denise Chong | Denise Alexander | Thomas Nickerson (ATSF) |
On May 4, 2011, Themmen appeared on the ITV Breakfast programme, Daybreak, alongside the other child actors from Willy Wonka & the Chocolate Factory: Peter Ostrum (Charlie Bucket), Julie Dawn Cole (Veruca Salt), Denise Nickerson (Violet Beauregarde) and Michael Bollner (Augustus Gloop).