The husband and wife presenting duo – who co-hosted the show for 13 years - were invited back to the studio in honour of the breakfast programme's 21st anniversary.
They joined current hosts Phillip Schofield and Holly Willoughby to reminisce about their time on This Morning.
And at one point it all got a bit much for Judy, 61, who was brought to tears by an old video showing her children on the show.
"I feel a bit tearful when I look at (old footage) because it's so entwined with our children's lives," she admitted.
On October 3, 1988 Richard, 53, and his wife launched the popular daytime magazine show from Liverpool, announcing they would be "on the air for the next two hours" and "had something for all the family."
To add to the day's nostalgic feel, the opening credits from the inaugural show were played.
Among the stories recollected from This Morning's history was one in which resident doctor Chris Steele demonstrated how to perform a testicular examination on a live model.
"The surprise was, in rehearsal the guy hadn't shaved and when we went live, he had shaved," Richard remembered. "We almost all collapsed in fits of laughter."
Talking about their decision to leave the show in 2001 and move to Channel 4, the dad-of-two added: "It wasn't that we'd had enough of This Morning, because how could you? It's the best gig in town."
"We look back on This Morning with huge nostalgia and affection. We hear the music sometimes in the kitchen and think: 'Oh yeah, we started that!"