Fast & Furious actor Paul Walker mourned
Fans, friends and fellow stars have been paying tribute to US actor Paul Walker, who has died in a car crash.
Walker was best-known for playing Brian O'Conner in the Fast & Furious films.
The 40-year-old died on Saturday when a Porsche being driven by a friend, who also died, crashed near Los Angeles.
"Brother, I will miss you very much," Diesel said on Twitter.
In a second message, he said: "My heart is hurting so sad. Paul Walker was a good man. RIP my friend... Sorry to the Walker family."
Walker starred in five of the six movies in the popular Fast & Furious franchise and had started filming the seventh.
The accident happened while Walker was attending an event for his charity Reach Out Worldwide.
The Los Angeles County Sheriff's department said deputies found a car engulfed in flames when they responded to a report of a collision. Two people found in the car were pronounced dead at the scene.
Images showed the burned-out wreckage of a red Porsche by the side of the road.
"It is with a truly heavy heart that we must confirm that Paul Walker passed away today in a tragic car accident while attending a charity event for his organisation Reach Out Worldwide," a statement on the actor's Facebook page said.
"He was a passenger in a friend's car, in which both lost their lives. We... are stunned and saddened beyond belief by this news.''
Other tributes came from Dwayne "The Rock" Johnson, who has appeared in two Fast & Furious films. "All my strength, love & faith to the Walker family during this heartbreaking time," he wrote.
"We find our strength in his light. Love you brother."
Actress Jessica Alba, who appeared alongside Walker in the 2005 diving drama Into the Blue, described him as "a lovely person - so sweet and grounded".
Director Rob Cohen, who cast Walker in the first Fast & Furious picture as well as the 2000 drama Skulls, told Variety magazine that Walker and Vin Diesel were "the perfect duo for me".
Speaking about Walker, the director said: "His American beauty, his athleticism, the directness of his approach to the character, his effusive, down-to-earth personality brought joy to me and everyone around him.
"I will miss him all the rest of my days."
Ludacris, another co-star, recalled : "Your humble spirit was felt from the start, wherever you blessed your presence you always left a mark."
In the Fast & Furious films, Walker made his name playing undercover officer Brian O'Conner, who infiltrated a gang of illegal Californian street racers before switching allegiances to join them.
As well as those five movies, Walker's other credits included Flags of Our Fathers, Eight Below, Noel and the forthcoming Hurricane Katrina drama Hours.
Universal Pictures issued a statement saying Walker was "truly one of the most beloved and respected members of our studio family for 14 years".
"This loss is devastating to us, to everyone involved with the Fast & Furious films, and to countless fans," it said. "We send our deepest and most sincere condolences to Paul's family."
Walker began acting as a young boy when his mother, a model, took him to auditions for commercials.
He won roles in the TV series Touched by an Angel and The Young and the Restless before moving on to supporting roles in late 1990s films like with Varsity Blues and She's All That.
After the success of the first Fast & Furious film, Walker became the leading man for the second instalment when Vin Diesel dropped out.
Diesel later returned, however, and the six-film franchise has now earned an estimated $2.4bn (£1.5bn) at global box offices. The latest instalment, the sixth, was the most lucrative so far.
The seventh instalment began filming in September but has not been completed. It had been scheduled for release in July.
Another forthcoming film is Brick Mansions, a remake of the French action film District B13, for film studio Relativity.
Relativity President Tucker Tooley said in a statement: "Paul was an incredibly talent artist, devoted philanthropist and friend."