The Downing Street said that the two leaders discussed “foreign policy issues and global trade” during the call on Friday evening, the BBC reported.
Johnson and Trump “looked forward to speaking further” at the summit, it added.
This will be the first time Johnson will meet Trump after becoming Prime Minister.
Trump has consistently praised Johnson, and predicted a speedy US-UK trade deal after Brexit.
The G7 meeting in Biarritz, a get together of most of the leaders of the world’s largest economies, comes with just over two months until the UK is scheduled to leave the European Union (EU) on October 31.
Johnson will meet European Council President Donald Tusk on Sunday in their first face-to-face meeting.
The G7 Summit follows a hectic week of diplomacy for Johnson, who visited Paris and Berlin in an effort to persuade the EU to amend the withdrawal agreement it reached with his predecessor Theresa May, the BBC reported.
The Summit, which also comprises Canada, France, Germany, Italy, Japan and the US, runs from Saturday to Monday.
Issues on the agenda include the global economy, tackling inequality and responding to the challenges of the digital age and the rise of Artificial Intelligence.