Oprah would lose to Joe Biden - poll

If Oprah Winfrey decides to run for the US presidency in 2020, her toughest opposition might not come from Donald Trump.

A new poll has found the TV mogul would lose to former Vice President Joe Biden in a Democratic primary, the Guardian reports.

Slightly more than three-quarters of Democrats polled had a favourable view of Mr Biden, who served eight years as Barack Obama's deputy between 2009 and 2017.

Only two-thirds had a positive view of Ms Winfrey, about the same as Bernie Sanders, who lost in the 2016 primary to Hillary Clinton.

All three were ahead of Elizabeth Warren, who's often touted as a potential candidate in 2020.

In a four-way race, the Guardian reports Mr Biden would come out on top, followed by Mr Sanders, then Ms Winfrey.

Mr Trump says it "would be a lot of fun" to run against his old friend, but is sure he'd win. A Rasmussen poll found she would likely beat him by 10 points, but as Ms Clinton found in 2016, getting the most votes doesn't necessarily result in victory thanks to the United States' Electoral College system.

Speculation has surrounded Ms Winfrey's intentions since she gave a rousing speech at the Golden Globes earlier this month.