Katie Holmes and Joshua Jackson Leaning on Each Other Amid Loss of Former Costar James Van Der Beek

Crushed Katie Holmes and Joshua Jackson are devastated by the death of fellow Dawson’s Creek castmate James Van Der Beek, and the friendly exes are leaning on each other for support and vowing to maintain their fallen friend’s legacy, sources say.

Katie and Joshua, both 47, starred in the WB teen drama — which aired from 1998 to 2003 — alongside James, who succumbed to colorectal cancer at age 48 on Feb. 11.

The passing of the Varsity Blues hunk was announced by his widow, Kimberly, and came 15 months after he publicly revealed his stage 3 diagnosis.

An insider says of Katie and Joshua, “Neither of them want to accept this. James was just the greatest guy. It’s a huge loss — and not just for them. They are devastated for his six kids and his wife. He fought so hard to stick around for them, and for a long time, it seemed like he was going to beat this. So to have him not make it is very hard to take.”

Kimberly and James married in 2010 in Tel Aviv, Israel, after a whirlwind romance, and five years ago, they left California and settled in Texas, where they’d been raising their family.

Joshua stars in Katie’s new film trilogy Happy Hours, and the two have remained close over the years, sources say.

“They already talk all the time, so it’s natural they are helping support each other through this,” the insider shares. “Katie is a very proactive person, so she wants to arrange something that she and Josh and the rest of the cast can contribute to — a video memorial sort of thing — with all their favorite James memories. That way his kids can have that. She will spearhead it, but Josh is all in.”