Hammond was May's first appointment when she moved into 10 Downing Street last summer, but there have been increasing suggestions of a rift between the pair.
Asked twice to guarantee Hammond's future after the election earlier today, May declined to do so.
"The chancellor and I and every other member of my tam are focused on June 8. Our focus is on winning this election, because it matters for the future of our country," May said.
Pressed a second time, May and Hammond smiled and shook their heads, with Hammond answering: "We work very closely together. The Prime Minister and I have known each other for many, many years. we work very closely together.
"She's got an extremely strong team around her. I work very closely with her team. Indeed some of them are people that I've known for many, many years. We do work very well together as a team. And all this media tittle-tattle is just that. Media tittle-tattle."
Hammond's comments are a reprise of a defence deployed this morning, when he told BBC Radio that suggestions of a rift with May's co-chief of staff Nick Timothy were "tittle-tattle".
Asked a final time whether she would offer the chancellor an endorsement, the Prime Minister said she was "happy to do so".
She added: "We have worked together over the years, for many years, longer than we would care to identify. That's an age-related comment, rather than anything else, just in case you try and read anything into that."
The lack of certainty on Hammond's future is important, because it has repeatedly been the chancellor that has moved to reassure the City over its' future through Brexit.
Last year, it was Hammond stressing that financial services would be prioritised in talks, that new immigration rules would not rule out highly-skilled workers coming to the UK, and that "thoughtful politicians" should back transitional deals.
However, his approach has put him at the centre of briefing wars in parliament, with Cabinet colleagues last year bemoaning the chancellor's tendency of "thinking like an accountant seeing the risk of everything".