Alonzo Hawk is the name of a scheming villain in various Disney movies, played by Keenan Wynn.
― Anonymous User 1/24/2019
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The year before Doctor Who, "Allons-y, Alonzo" appeared as dialogue in the movie Pierrot le Fou (1965) by Jean-Luc Godard, although it's possible that it's a common francophone pun.
Alonzo Andretti Muhlach, also known as Alonzo Muhlach, is a Filipino child actor. He is known for his role as Prinsipe Vladimir in My Big Bossing segment: Prinsesa. In January 2017, he joined the kid's version of Your Face Sounds Familiar Kids on ABS-CBN.
Alonzo was the first name of Midshipman Frame in the first episode of Doctor Who season three. The Doctor said, "There's something else I've always wanted to say: allons-y, Alonzo!"