Aston Merrygold, Marvin Humes, Ortisé Williams and JB Gill will use the service to chat to four fans, selected via Twitter, in the coming weeks.
JLS said: "We all love BlackBerry and BBM, so we're pretty excited about the arrival of BBM Voice.
"With our hectic schedule, BBM Voice is a great way for us to keep in touch with friends and family back home.
"It's also a great opportunity to give something back to our fans and we're looking forward to giving four winners the chance to ask us their burning questions!"
From January 7, fans can follow the @UK_BlackBerry Twitter profile and fill in gaps in its tweets to win the chance to talk to the boyband stars.
BBM with voice functionality launched last month and allows BlackBerry users to make free voice calls to their contacts via a WiFi connection.