Was it when he played troubled T. J. Latimer in the angst-ridden Family (1976-77)?
Shipwreck survivor Fred Robinson in The Swiss Family Robinson (1975-76)?
As early as his brief sitcom appearance as Paul Sorvino's kid in We'll Get By (1975)?
Certainly by the time he landed the role of troubled Tommy Bradford in Eight is Enough (1977-81), Willie Aames and his muscles were superstars.
In 1979 Willie became even more famous for his semi-nude and nude screenshots in the Blue Lagoon rip-off Paradise, but gay teenagers were more interested in Zapped! (1982), in which he and Scott play lovers. Well, college students crazy about girls who nevertheless can't stop grinning at each other.
Intensive buddy-bonding with the dreamy Scott Baio on Charles in Chargefollowed (1984-1990), though in order to keep viewers focused on Scott's dreaminess, the producers had to minimize Willie's buffness. They made his character, Buddy Lembeck, stupid, the butt of jokes rather than the source of sighs.
Willie thankfully never sang, but that didn't keep the teen magazines from going into hysterics about his incredible talent -- by which they meant physique.
After Charles, drug and alcohol addiction took their toll, and Willie's acting career fizzled. A stint as Christian fundamentalist superhero Bible Mandidn't help him regain his followers or his fame. In 2005, he produced, wrote, directed, and starred in The Public Life of Sissy Pike, about a Christian fundamentalist girl.
There are nude photos of Willie Aames on Tales of West Hollywood.