Bell, 35, and Gad, also 35, spent time with Menzel at a benefit for the 44-year-old actress' charity, A Broader Way. Bell and Menzel, who voiced sisters Anna and Elsa in Frozen, performed together at the event Sunday.
"Singing #frozen songs with the effervescent @idinamenzel at a benefit for her @abroaderway foundation," Bell captioned a photo of herself onstage with Menzel.
"Team #Frozen back together again for #broader way. Love these girls! @kristenanniebell and @idinamenzel," Gad, who voiced Olaf, added to his own post.
Menzel founded A Broader Way in 2010 with her then-husband, actor Taye Diggs. The foundation provides "an outlet for self-expression and creativity through arts-centered programs" for girls, with an emphasis on leadership and self-esteem.
Frozen opened in theaters in 2013 and earned a whopping $1.27 billion at the box office. Disney announced plans for a sequel last March, but has yet to confirm Bell, Menzel and Gad are returning.
"I would play Anna forever if they would let me," Bell told CBS News after the announcement. "Not only do I enjoy the character and how much people love her, but I enjoy the team -- the physical production team that I get to work with."
Bell plays Jeannie Van Der Hooven on Showtime series House of Lies, which will return for a fifth season April 10. Gad will voice Le Fou in Disney's live-action adaptation of Beauty and the Beast and Chuck in The Angry Birds Movie.