'Slap on the face of the former guy’: Trump mocked after Boris Johnson hails Biden as a ‘breath of fresh air’

After meeting President Biden for the first time ahead of the G7 Summit, U.K. Prime Minister Boris Johnson said the U.S. President is a "breath of fresh air" while speaking to reporters.

"It's new, it's interesting and we're working very hard together. We went on for about an hour and 20 or so. It was a long, long, good session. We covered a huge range of subjects," Johnson said, according to reports.

"It's wonderful to listen to the Biden administration and to Joe Biden, because there's so much they want to do together with us, from security, NATO, to climate change." he added.

The comments caught some off guard, since Johnson was known to be an ally of former President Donald Trump.