They're both blonde, busty and mononymous. 

Dagmar was all over the TV Airwaves in the 1950s, appeared on broadway, and even had a top 40 (#21) song called "Mama Will Bark" duetting with Frank Sinatra. And many thought it was a dog...groannnnn. But how many people can say they made the cover of Life magazine?? Mitch Miller wanted Frank to do the song and since Frank had been familiar with Dagmar as an opening act and on his TV show, he agreed.  Later, he was embarassed by the song and fumed at Mitch Miller that the song "ruined his career"! 

Here's a TV clip of Dagmar (from The Frank Sinatra Show in 1951) doing a nice job singing “Ballin the Jack” 

During the same time-period that Dagmar was steaming up the States, Sabrina was busting out on the British tube and screens.  A few minor movie roles, an appearance on Tarzan and a slew of glamorous pin-up shots is what she left us with.