The source also said that children are a top priority for the couple and that "Katy wants to have her first kid soon after they get married."
Speaking about their engagement to Kiss FM earlier this year, Katy said that she and Orlando are "taking things one step at a time" in terms of their wedding planning.
"We're definitely trying to lay a good emotional foundation for the lifetime of commitment, which is a big deal to me," she explained.
Katy married comedian Russell Brand on October 2010 before he famously filed for divorced in December 2011 right before she went on stage to perform a concert in Brazil. Orlando was married to Miranda Kerr from 2010 to 2013 and they have an 8-year-old son, Flynn, together.