Kate Middleton, Prince William getting ready for their Boston visit

Prince William, who alongside his wife Kate Middleton will travel to Boston for the second annual Earthshot Prize awards ceremony in December, caught up with Mayor Michelle Wu on Thursday via video chat to talk about the city's work on sustainability and ongoing preparations for the event.

Kate Middleton and William would make the trip across the pond for the awards ceremony. 

During their visit, the Prince and Princess of Wales will also spotlight and celebrate the "inspiring" city for their work on addressing the impacts of climate change and building a resilient future, they said in a statement.

The royal couple were last in the U.S. in 2014 during their visit to New York. Their first visit to the U.S. together was shortly after their royal wedding in 2011 when they headed to Los Angeles.

Kate and William won't have the time to meet Meghan Markle and Prince Harry during their US royal tour.