They were Fred and Ethel and the last name was Mertz or (Merts) on "I Love Lucy"
Fred
Mcgillicuddy
May 6, 1957.
I Love Lucy - 1951 Hollywood at Last 4-16 was released on: USA: 7 February 1955
I Love Lucy - 1951 Paris at Last 5-18 was released on: USA: 27 February 1956
I Love Lucy/The Lucy Show had the last name of "Mcgillicutty" in it. Maybe that's what you were thinking of...?
The late Lawrence Dobkin (September 16, 1919 - October 28, 2002) was in two 'I Love Lucy' episodes : "Equal Rights" and "Paris at Last" .
Desi Arnaz Jr. did appear in the very last episode of "I Love Lucy" along with his sister, Lucie Arnaz in 1957. Both Arnaz children made a cameo appearance in that episode,
Lucille Ball and Desi Arnaz
There wasn't one, Lucy and Desi got divorced so they finished the last three seasons(which was 7,8,and 9 and known as the "lucy-desi comedy hour") the last show wasLucy meets the moustache original air date 4-01-1960
It's not what you'd expect. The last episode of the last season, season 6, episode 179, is called "The Ricardo's dedicate a statue". Their Connecticut town is having a Revolutionary War re-enactment. However, the show actually filmed several one hour episodes after the last "full" season, which are now available as one DVD set that is labeled as "Seasons 7,8, & 9".
Madelyn Pugh-Davis, a writer for the show, grew up in Indianapolis and knew a boy whose last name was Mertz. He later became a Doctor in Indianapolis. That is where the last name came from. She used it because she thought it sounded funny!