Yesterday (Wednesday, March 3) Dominic Keating guest-starred on CSI: New York, on episode 6x16, "Uncertainty Rules".
According to the press release,
On the night of a young man's 21st birthday, his friends take him out to celebrate, but when they turn up dead and he's found walking in the middle of the street covered in his friends' blood and wielding an axe, the CSIs must trace the events of the man's wild night to figure out just what happened.
Dominic plays a character called Rufus Knox.
Thanks to Fred "The_Middleman" for the info. :)