The titular character of Temperance "Bones" Brennan is played by Emily Deschanel. Her main love interest, Seeley Booth, is played by David Boreanaz. Michaela Conlin and TJ Thyne are the only other actors to have appeared on every episode of the show.
The two next-longest tenured actors on the show are Tamara Taylor and John Francis Daley, who arrived on the second and third seasons respectively. Several notable celebrities have appeared on the show as guest stars as well. ZZ Top member Billy Gibbons, British comedian Stephen Fry and singer Cyndi Lauper are among the famous people to have appeared on "Bones" on several occasions.