Bob LeMond: It's time for My Favorite Husband starring Lucille Ball!
Lucille Ball: Jell-O, everybody!
Theme music [composed by Marlin Skiles, conducted by Wilbur Hatch]
LeMond: Yes, it's the gay family comedy series starring Lucille Ball with Richard Denning and is brought to you by the Jell-O family of Red-Letter Desserts:
O! The big red letters stand for the Jell-O family,
Oh, the big red letters stand for the Jell-O family,
Yum, yum, yum!
Yum, yum, yum!
Jell-O tapioca pudding, yes sir-ee!
LeMond: Now, let's take a look at the Cooper family, two people who live together and like it.
The program, which aired 124 episodes from July 23, 1948, through March 31, 1951, initially portrayed the couple as being a well-to-do banker and his socially prominent wife, but three new writers—Bob Carroll, Jr., Madelyn Pugh, and Jess Oppenheimer—took over the writing, changed the couple's name to Cooper, and remade them into a middle-class couple, which they thought average listeners would find more accessible.
Lucille Ball was asked to do a television version of the show (with Jell-O remaining as sponsor), and CBS insisted on Richard Denning continuing as her co-star. However, Ball refused to do a husband-and-wife TV show without real-life husband Desi Arnaz playing her on-screen husband. The network reluctantly agreed, reworking the concept into I Love Lucy after Ball and Arnaz took a show on the road to convince the network that audiences would respond. When Jell-O dropped out of the show, Philip Morris became the television sponsor.
Carroll, Pugh and Oppenheimer agreed to do the switch to I Love Lucy. They subsequently reworked several My Favorite Husband episodes into I Love Lucy episodes, especially early in the TV show's run. For example, the 1948 radio episode entitled "Giveaway Program" inspired the I Love Lucy episode "Redecorating", with some lines exactly the same. Many actors who had done the My Favorite Husband radio show also appeared on I Love Lucy, sometimes in episodes where they reprised their roles using a reworked My Favorite Husband script.
Sources: Wikipedia and LucyFan.com