Has two older brothers, Holt and John; and older sister, Meg. Brother Jason died from head injuries suffered in a car accident
when she was very young.

Auditioned for all 3 female leads on "Roswell" (1999) before being cast as Isabel.

She is half Irish and half German.

Began dating Joseph Lawrence in 1994. They met at Seventeen Magazine's 50th Anniversary party.

1996: Graduated from New Canaan High School.

Beat out Alicia Silverstone for the lead role in My Father the Hero (1994).

Played the cello in High School.

Ranked #72 in Stuff magazine's "102 Sexiest Women In The World" (2002)

Has the same birthday as her former "Roswell" (1999) co-star Colin Hanks.

Her last name is pronounced "HI guhl."

Has played a character with the name of "Isabel" or "Isobel" three times. "Grey's Anatomy" (2005), "Roswell" (1999) and
Wuthering Heights (2003) (TV).

Ranked as #55 in FHM's "100 Sexiest Women in the World 2005" special supplement. (2005)

Cut & dyed her hair for season 3 of "Roswell" (1999).

June 2006: Engaged to musician Josh Kelley.

In Judd Apatow's film, The 40 Year Old Virgin (2005), the FHM "100 Sexiest Women in the World 2005" special supplement with
Katherine on the cover is shown in close-up during a scene on the extended version DVD. Katherine plays the lead in
Apatow's follow-up, Knocked Up (2007).

2006: Named #19 in FHM magazine's "100 Sexiest Women in the World 2006" supplement.

Ranked #14 on the Maxim magazine Hot 100 of 2007 list.

Was writer/director Judd Apatow's first choice for the lead role in Knocked Up (2007).

2005: She was October on FHM magazine's 2005 pin-up calendar.

Plans to marry fiancé Josh Kelley, on December 23, 2007 in Utah where she has a ranch property. There will be a tribute to her
late brother, Jason, at the ceremony [July 18, 2007].

Best friend of her "Grey's Anatomy" (2005) co-star T.R. Knight, who was a groomsman at her wedding.

Was named one of Entertainment Weekly's Top 25 Entertainers Of The Year (2007).

Is related to actress Amber Perkins.

Auditioned for the role of Felicity Porter in the TV series "Felicity" (1998), but lost out to Keri Russell. She also auditioned for the
roles of Sydney Bristow andLauren Reed on "Alias" (2001), but lost out to Jennifer Garner and Melissa George, respectively.

Voted as #1 in 2008's Askmen.com "Top 99 sexiest women in the world" poll. (2008).