Watkins, 36, pleaded guilty in Cardiff Crown Court to 13 child sex offenses last month, but he insisted he was a drug addict with no recollection of the acts.
The BBC said Watkins is expected to serve 29 years behind bars before he is eligible for parole.
His two co-defendants -- fans of the musician and the mothers of the abused children -- were also sentenced to 14 and 17 years in prison respectively, the British broadcaster said.
The women's identities have not been officially released to the public.
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