Frank Sinatra dominated pop culture for decades in the 20th century. So it's no surprise that America's top crooner - who was born 101 years ago this week - had some unusual collaborations over his career. Here's a look back at some of his stranger duets and partnerships over the years. 

1. Elvis Presley

After dominating popular music for years, crooners began to lose ground in the charts to rockers by the late 1950s. So you wouldn't be surprised if established singers like Frank Sinatra resented newcomers like Elvis Presley. But that wasn't the case in 1960, when Old Blue Eyes hosted a televised welcome home party for Elvis, who had just returned to America following his tour of military service in Germany.

During the show, the two singers teamed up for a medley of their hits, with Frank crooning Love Me Tender and Presley rocking Witchcraft.

2. Sammy Davis Jr.

Nowadays, no one is surprised to see clips of Sinatra singing alongside fellow Rat Pack member Sammy Davis Jr. But performing with a black entertainer was a controversial move at the time - especially in Las Vegas, where Sinatra fought for Davis to be treated like any other celebrity.

"In the days when Las Vegas began to become popular, the black performers could play in the showrooms, but they couldn't stay in the hotel," Frank Sinatra Jr. told George Stroumboulopoulos in 2012. "And it was Frank Sinatra who went to the people who were on the board of directors in those days....He said, 'Are you guys going to come into the 20th century or aren't you?'"

And when one of them hummed and hawed about color, Sinatra added, "The money's green. How about that?"

3. Nancy Sinatra

In 1966, Frank crossed genres by singing a poppy tune with his daughter Nancy. He made a solid effort to give his daughter's career a boost, even though he couldn't help mocking the vapid lyrics of Downtown while Nancy slipped a few verses from These Boots Are Made For Walking into the duet. 

4. Ronald Reagan

In 1978, then former Governor Reagan teamed up with Jimmy Stewart, George Burns, members of the Rat Pack and other stars for the celebrity roast of Frank Sinatra. During the event, the future president offered a mock stump speech for Sinatra to run for the White House in 1980.

"Frank Sinatra will make a president who is strong on defence," Reagan said. "But...will have concern for humanity. Scientists at his urging have developed an intercontinental ballistics missle that is not a weapon of mass destruction. It only hits photographers."

Reagan went on to win the 1980 election, so we'll never know what Sinatranomics would've looked like. 

5. Bono 

In the early 1990s, Frank Sinatra wrapped up his recording career by teaming up with old, current and upcoming stars for the albums Duets and Duets II - the 56th and 57th albums in his music career.

One of the more surprising pairings saw the American crooner sing alongside Bono of U2. 

"I don't usually hang with men who wear earrings," Sinatra told the Irish rocker before their session.

Maybe that's why they didn't appear onscreen together for the music video.

Banner image: Sinatra with Dean Martin and Judy Garland in 1962 (wikipedia.org)