The Friday afternoon session, which was due to be moderated by TVLine editor Michael Ausiello, has been called off as neither Emily Deschanel nor David Boreanaz are able to attend for personal reasons.
A representative for network Fox confirmed the news to The Hollywood Reporter, adding that Geoff Stults and Michael Clarke Duncan from Bones spinoff The Finder will still make an autograph signing at the Fox booth.
This event is due to take place at 3pm on Friday.
Deschanel is expecting her first child with husband David Hornsby later this year.
The new season of Bones will premiere on Thursday, November 3 on Fox. The show will take a mid-season break during which The Finder will make its debut.
Bones' executive producer Stephen Nathan has promised fans that "an extremely odd and fearless foe" will be introduced when the show returns.
Watch a clip from the sixth season finale of Bones below: