William Shatner has spoken of his sadness at the death of his former 'Boston Legal' co-star Justin Mentell.

Actor Justin, 27, died as the result of a car accident on Monday (01.02.10) when his Jeep went off a steep embankment and hit two trees, throwing him from the vehicle in Wisconsin, US, in the early hours of the morning.

Former 'Star Trek' star William tweeted: "I'm deeply saddened to hear about Justin Mentell. There's no telling how far up the ladder he may have climbed. My sympathies to his family."

Police said Justin wasn't wearing his seatbelt at the time of the time of the crash.

The actor had played attorney Garrett Wells in 'Boston Legal' until its second series in 2006, when his character disappeared without explanation. He most recently voiced the character Terrell in Disney's FBI trained animal comedy film 'G-Force'.