Linkin Park lead singer Chester Bennington was found dead Thursday morning in his Palos Verdes Estates home, on what would have been Soundgarden frontman Chris Cornell’s 53rd birthday. The two singers were close friends.

Also Read: Chester Bennington, Lead Singer of Linkin Park, Commits Suicide at 41 (Report)

Cornell died by hanging himself in May, and Bennington apparently killed himself the same way, according to multiple reports that cite local law enforcement (TMZ was first to report the news). The singer had struggled with drugs and alcohol for years, according to the outlet.

Also Read: Brad Pitt, Rock Greats Mourn Chris Cornell at Funeral

After Cornell’s death, Bennington tweeted out a letter to his friend. “I’m still weeping, with sadness, as well as gratitude for having shared some very special moments with you and your beautiful family,” Bennington wrote. “You have inspired me in many ways you could never have known. Your talent was pure and unrivaled. Your voice was joy and pain, anger and forgiveness, love and heartache all wrapped up into one… I can’t imagine a world without you in it.”

Also Read: Chris Cornell's Widow Says Prescription Drugs May Have Played Role in Suicide Death

Linkin Park also dedicated their song “One More Light” as a tribute to Cornell on “Jimmy Kimmel Live!”

“We were going to come out and play heavy first, but in light of our dear friend Chris Cornell passing away, we decided to play our song ‘One More Light’ in honor of him to start this off,” Bennington said at the performance in May.

Bennington is survived by six children, and he was married twice.