Mary Elizabeth Chieffo (born November 7, 1992) is an American actress known for portraying the Klingon L'Rell on the television series Star Trek: Discovery.

[3] She grew up in the neighborhood of Valley Village, Los Angeles in California, only daughter of actors Michael Chieffo and Beth Grant.

[3] She attended the Drama division of Juilliard School in New York City, earning a Bachelor of Fine Arts degree in 2015.

[5] Chieffo came out publicly as a lesbian on the red carpet prior to the Star Trek Day event held September 8, 2021, at the Skirball Cultural Center in Los Angeles, California.

[8] Chieffo wrote the introduction essay for the 2023 edition of Marvel's Voices: Pride #1,[9] reflecting on the need for queer representation in media.