Paul Walker's Death: 'Fast & Furious' Cast, Rihanna, Miley Cyrus React

'My heart is hurting so bad,' wrote co-star Tyrese Gibson.

Following Paul Walker's death on Saturday
 in a car crash in Southern California, "Fast & Furious" co-stars Ludacris, Tyrese Gibson and Vin Diesel were among the stars who posted tributes to their fallen comrade.

"Brother I will miss you very much. I am absolutely speechless," wrote longtime "Furious" co-lead actor Diesel along with a picture of the pair. "Heaven has gained a new Angel. Rest in Peace."

The music world was also deeply affect, with Rihanna expressing her condolences, writing, "Very very sad news .. I'm so heartbroken about this!" as well as Miley Cyrus, who said, "I'm really sad about Paul Walker :(" Justin Bieber tweeted, "RIP Paul Walker."

Other "Fast" co-stars, including Dwayne "The Rock" Johnson, also weighed in, saying, "All my strength, love & faith to the Walker family during this heartbreaking time. We find our strength... in his light. Love you brother." Tyrese Gibson tried to make sense of it on his Facebook page. "My heart is hurting so bad no one can make me believe this is real," he posted alongside a photo of the two on set. "Father God I pray that you send clarity over this cause I just don't understand. My heart hurts it's broken no one can convince me that this is real ... Prayer warriors please pray real hard for his only child, his daughter."

Ludacris praised Walker's generous soul. "Your humble spirit was felt from the start," he wrote. "Wherever you blessed your presence you always left a mark, we were like brothers & our birthdays are only 1 day apart, now You will forever hold a place in all of our hearts @paulwalker legacy will live on forever. R.I.P."

Watching one of their own pass at such a young age touched a number of other young Hollywood stars, including "Glee"'s Jenna Ushkowitz, who wrote, "My thoughts and love go out to Paul's friends and family," as well as Olivia Wilde, who shared, "Heavy heavy heart tonight. Paul Walker was a genuinely good, sweet, kind, laid back, loving person. Sending much love to his family."

Former "Breaking Bad" star Aaron Paul posted his goodbye with, "My heart goes out to [daughter] Meadow and everyone else affected by this terrible loss. We will miss you my friend. We Love you."

Latest Information In The Death Of Paul Walker.

Among other tributes:

»Ariana Grande: What a tragedy. Cherish every moment with your friends, family & loved ones. You never know what could happen. Heartbreaking #RIPPaulWalker."

»Michael B. Jordan: "Man life is so short. People you care about can be here one min and gone the next. Don't take life for granted. RIP Paul Walker."

»James Franco: "#paulwalker -- much love to Paul Walker. So sad. He gave a lot of joy."

»Zoe Saldana: "A very sad day indeed. R.I.P. Paul Walker. Our prayers are with you and your family."

»Amber Riley: "My condolences to Paul Walker's family. Rest in Peace."

»Bella Thorne: "Love and prayers to the family of Paul Walker."

Fans also expressed their thoughts, with one, Isabella Montez, writing, "FF movies are never gonna be the same. RIP Paul, we will miss you."

Investigators are trying to determine if excessive speed played a role in the single-car accident, which took place around 3:30 p.m. on Saturday, according to the Los Angeles Times. Both Walker and another person were killed in the crash, which left the vehicle in flames.