Question: Which star of Pitch Perfect was born on July 31, 1989 ?

Context paragraphs:
Hailee Steinfeld: Hailee Steinfeld (born December 11, 1996) is an American actress and singer.  She first became known for her portrayal of Mattie Ross in "True Grit" (2010), which earned her an Academy Award nomination.  Thereafter, she appeared as Petra Arkanian in "Ender's Game" (2013), Juliet Capulet in "Romeo & Juliet" (2013), Violet Mulligan in "Begin Again" (2013), Zooey Renner in "3 Days to Kill" (2014), Emily Junk in "Pitch Perfect 2" (2015) and "Pitch Perfect 3" (2017), and Nadine Franklin in "The Edge of Seventeen" (2016), the last for which she received a Golden Globe Award nomination.

Alexis Knapp: Alexis Merizalde Knapp (born July 31, 1989) is an American actress and singer.  She is known for her role as Stacie Conrad in the musical films "Pitch Perfect" (2012) , "Pitch Perfect 2" (2015) and the upcoming "Pitch Perfect 3".  She is also known for her role of Alexis in the party film "Project X" (2012), and her role on the first season of the TBS comedy "Ground Floor".

Pitch Perfect: Pitch Perfect is a 2012 American musical comedy film written by Kay Cannon and directed by Jason Moore.  It features an ensemble cast, including Anna Kendrick, Skylar Astin, Rebel Wilson, Anna Camp, Brittany Snow, Ester Dean, Alexis Knapp, Hana Mae Lee, Adam DeVine, Ben Platt, John Michael Higgins, and Elizabeth Banks.  The plot follows Barden University's all-girl a cappella group, The Barden Bellas, as they compete against another a cappella group from their college to win Nationals.  The film is loosely adapted from Mickey Rapkin's non-fiction book, titled "Pitch Perfect: The Quest for Collegiate a Cappella Glory".  Filming concluded in December 2011, in Baton Rouge, Louisiana.

Hana Mae Lee: Hana Mae Lee (born September 28, 1988) is an American actress, model, comedian, and fashion designer.  She is best known for playing Lilly Okanakurama in the 2012 film "Pitch Perfect" and its sequel "Pitch Perfect 2" (2015).  She also owns her own fashion line titled "Hanamahn".

Pitch Perfect 3: Pitch Perfect 3 is an upcoming American musical comedy film directed by Trish Sie and written by Kay Cannon.  A sequel to "Pitch Perfect 2" (2015) and the third and final installment in the "Pitch Perfect" trilogy, the film will star Anna Kendrick, Anna Camp, Rebel Wilson, Brittany Snow, Hailee Steinfeld, Alexis Knapp, Ester Dean, Hana Mae Lee, Chrissie Fit, Kelley Jakle and Shelley Regner, with Elizabeth Banks and John Michael Higgins.  The film is scheduled to be released on December 22, 2017.

Kelley Jakle: Kelley Alice Jakle (born June 27, 1989) is an American actress and singer-songwriter.  She is best known for her role as Jessica in "Pitch Perfect" (2012) and its sequel "Pitch Perfect 2" (2015).  She is also known for her appearances on the first and second seasons of "The Sing-Off" in 2009 and 2010.

Skylar Astin: Skylar Astin Lipstein (born September 23, 1987), known professionally as Skylar Astin, is an American actor and singer.  He became known for portraying Jesse Swanson in the musical films "Pitch Perfect" (2012) and "Pitch Perfect 2" (2015).  He was also in the original cast of the Broadway musical "Spring Awakening", and has since appeared in films such as "Hamlet 2" (2008), "Taking Woodstock" (2009), "Cavemen" (2013), and "21 & Over" (2013).

Anna Camp: Anna Ragsdale Camp (born September 27, 1982) is an American actress and singer.  She is known for her role as Sarah Newlin in "True Blood", and her recurring roles in "Mad Men", "The Good Wife", and "The Mindy Project".  She is also known for her role as Aubrey Posen in "Pitch Perfect" (2012), "Pitch Perfect 2" (2015), and the upcoming "Pitch Perfect 3" (2017).  She made her Broadway debut in the 2008 production of "A Country House" and played Jill Mason in the 2008 Broadway revival of "Equus".  In 2012, she was nominated for a Drama Desk Award for her performance in the Off-Broadway play "All New People".  Camp played Jane Hollander, a researcher for the fictitious "News of the Week" magazine in the Amazon series "Good Girls Revolt."  She also had a role in the 2011 film "The Help".

Shelley Regner: Shelley Anne Regner (born December 21, 1988) is an American actress and singer known for her role as Ashley in the musical films "Pitch Perfect" (2012) and its sequel "Pitch Perfect 2" (2015).  She will be returning for the third installment, "Pitch Perfect 3" (2017).

Pitch Battle: Pitch Battle was a singing show hosted by Mel Giedroyc on BBC One.  It began airing on 17 June 2017.  It is a show which sees rival musical groups facing-off against each other.  The series is inspired by the 2012 film, "Pitch Perfect".  At the final on 22 July 2017, Leeds Contemporary Singers were crowned the winners.

Supporting paragraphs: Pitch Perfect Alexis Knapp
Answer: Alexis Knapp