Kelly Chambers appears in Mass Effect 2, and she is Shepard's Yeoman on the Normandy SR-2. Her primary job on the Normandy is to keep Commander Shepard abreast of new e-mails and pass on meeting requests from Shepard's squad mates. In addition, Kelly provides counselor support and monitors the psychological state of Shepard and the crew, offering input on mission outcomes and impressions on Shepard's team. Her abilities as a counselor and her impressions are influenced by her education where Kelly graduated with a psychology degree. In the Cerberus organization, she is identified as a member of the Lazarus Cell.
If Shepard asks her about Cerberus' notorious reputation, Kelly refutes the notion that she or the organization is anti-alien. While she does believe in the importance of Cerberus' agenda to benefit humankind, Kelly doesn't believe that it means they hate other species by default. Throughout her time on the Normandy SR-2, Kelly regards aliens with the same respect and compassion she feels for her fellow mankind, evidenced by her repeated displays of concern over Shepard's non-human companions.
She is initially identified and titled as "Yeoman Chambers", but if you respond positively at her suggestion to call her "Kelly", she will be identified as such. Alternatively, as Shepard interacts more with her, she will be addressed as "Kelly Chambers" and will eventually be referred to as "Kelly", possibly to show a growing camaraderie between Shepard and the crewmates.
Kelly is voiced by Cara Pifko
Kelly is a potential romance option for both male and female Shepard, though romancing her does not grant the Paramour achievement nor affects any relationship Shepard might have, whether it is with their current squad member or love interest from the first Mass Effect.
Shepard can flirt with Kelly anytime prior to the suicide mission, which eventually results in a private dinner at the Captain's Cabin, after which she offers to feed Shepard's fish. It is still possible to pursue a relationship with a squadmate after this point if the player is solely interested in having her feed Shepard's fish. If Kelly is among the crewmates saved from the Collector's base, and if Shepard currently has no existing romance partners, she will send a message on the terminal telling Shepard to use the intercom to invite her up into Captain's Cabin. This will not happen immediately after the game proper has finished. Take the Normandy to another star system first and then Shephard will receive a discreet message on their private terminal from Yeoman Kelly, saying she would like to meet the Commander privately and will wear something that is not exactly the recommended ship's uniform. If then Shepard goes into the Captain's Cabin, on the table right next to the terminal there will be the intercom option to call Kelly up (Shepard can do this repeatedly).
When Kelly is invited to Shepard's cabin, she will be seen sitting on the couch wearing an outfit similar to the ones worn by the dancers in Chora's Den and Afterlife. Shepard has three interaction options available; the first interaction is to have Kelly perform a series of dances, the second option is to have Kelly sit on Shepard's lap while the two caress each other, and the third and final option is to have Kelly and Shepard lie down together in bed, holding each other close with Shepard stroking Kelly's arm. Notably, among all the female romance options, Kelly is the only person who will dance and change her outfit for Shepard.
After the Normandy crew is abducted by the Collectors, Shepard must decide whether to travel immediately through the Omega 4 Relay to rescue the crew and destroy the Collector Base or to delay the mission in order to prepare themselves better.
If Shepard chooses the latter option, the team arrives just in time to see Kelly and other crew members get dissolved into raw organic material — which Doctor Chakwas describes as paste — used to create the Human-Reaper. If Shepard chooses to go through the Omega 4 Relay immediately, then Lilith, a colonist from Horizon, is liquefied, but Shepard and the squad free Kelly and the rest of the crew just in time. After releasing them from their pods, Shepard can choose to assign a squad member to lead the survivors back to the Normandy.
If Shepard saves Kelly in the suicide mission, the Yeoman recalls the events of her imprisonment vividly, reminiscent of Thane's memory recollection.