Encore: Movie Partners Sing Broadway, a collection of show tune duets featuring Hugh Jackman, Jamie Foxx and others, is her seventh number one album in the UK.
Encore recorded 20,000 combined sales, the Official Charts Company said.
In the singles chart, The Chainsmokers go top with Closer, the DJ duo's collaboration with US singer Halsey.
The Chainsmokers, aka Andrew Taggart and Alex Pall, said they were "beyond grateful at all the support from our UK fans".
"As a relatively new artist, it means a lot to us and gives us a lot of confidence in the music we have coming up," they said,
DJ Snake and Justin Bieber's Let Me Love You remains at two for the fourth straight week, one place above last week's number one record.
After five unassailable weeks in pole position, Cold Water - from Major Lazer and featuring Justin Bieber and MÃ˜ - drops to number three.
Calum Scott's Dancing On My Own and Twenty One Pilots' Heathens are non-movers at four and five respectively.
Twenty One Pilots occupy the same spot in the album chart, thanks to the US duo's fourth album Blurryface jumping six places to five.
The remainder of the top five is made up of Frank Ocean's Blonde at three, and Dolly Parton's Pure and Simple at four.
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Glory, Britney Spears' latest release, has been beaten to the top of the UK album chart by the 35th studio album from US music veteran Barbra Streisand.