Winning the contest may change Sampson and Prenger's lives
Britain's Got Talent beat I'd Do Anything in the Saturday night ratings war - after an average of 13.1 million saw George Sampson win the ITV show.
According to overnight figures, 6.9 million watched actress Jodie Prenger win the role of Nancy in the West End musical Oliver! on the BBC One show.
Both programmes were split into two shows and the BBC attracted an average of 5.1 million for the first one.
The early evening final of Britain's Got Talent drew in 11 million viewers.
That show peaked with an audience of 13 million and even more people switched on for the results with the highest rating throughout the show reaching 13.7 million.
Viewers voted teenage breakdancer Sampson the winner, after he performed his routine under a shower of water on stage.
The 14-year-old, from Warrington, has scooped the £100,000 prize money as well as a slot at this year's Royal Variety Performance in December.
He revealed afterwards that he had decided to change the music for his routine, just an hour before the curtain went up.
The teenager had originally been set to dance to a Bee Gee's track but chose Singing in the Rain instead.
"I wasn't sure about the choice of song and, about an hour beforehand, we changed it," he said.
"I probably wouldn't have won if I'd done the Bee Gees."
Viewing figures peaked to 7.3 million for the BBC talent contest in the later results show.
On hearing the result Prenger, 28, burst into tears and said she was "chuffed" to have been chosen by the voting public.