The War Machine actor, who was close friends with the late Soundgarden frontman, took Cornell’s children — Toni, 12, and Christopher, 11 — out for a day at the theme park on Wednesday.
“Brad loved Chris and of course will be there for his family,” a source tells PEOPLE.
Fans posted sightings of Pitt and the kids on social media throughout the day. They were spotted walking around Simpsons Land, sipping butterbeer from The Wizarding World of Harry Potter and riding the Jurassic Park-themed water coaster.
Last Friday, Cornell was laid to rest at Los Angeles’ Hollywood Forever Cemetery, just over one week after his shocking death in Detroit. He was found dead of suicide by hanging at MGM Grand Detroit following the band’s performance at the Michigan city’s Fox Theatre May 18.
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Pitt was in attendance at the funeral, where he was joined by other stars like Pharrell Williams, Christian Bale, Courtney Love, Dave Grohl and Taylor Hawkins of the Foo Fighters, Nirvana’s Krist Novoselic, Perry Farrell and Dave Navarro of Jane’s Addiction, Metallica’s Lars Ulrich and James Hetfield, Bush’s Gavin Rossdale, Pharrell, Billy Idol, Joe Walsh, Fred Armisen and James Franco.
While Cornell’s death was ruled a suicide, his family has stated that they didn’t believe Cornell to be suicidal. The star’s wife Vicky Karayiannis said she believes that the side effects of the prescription drug Ativan – which can cause worsening depression and thoughts of self-harm in rare cases – may have impacted Cornell. Toxicology reports are still pending, which may answer lingering questions about the circumstances of Cornell’s death.