The former EastEnders star was involved in a smash in Derby, England on Wednesday night after performing in a play. He is currently being treated for head injuries at the Royal Derby Hospital.
A spokesman for Derbyshire police says: "A 34-year-old man was taken to hospital after being involved in a road accident in Derby.
"The driver, who was the only person in the vehicle, was taken to the Royal Derby Hospital to be treated for head injuries. No other vehicles were involved and his injuries are not thought to be life threatening."
Gaffney's former EastEnders co-star, Spandau Ballet musician Martin Kemp, sent his best wishes to his friend on Twitter, writing: "All our love going out to deangaffney1 and his family... Get well soon buddy, I'm thinking of you!"
Blue singer Simon Webbe added: "Please say a prayer for a friend of ours Dean Gaffney who is fighting for his life right now. Our thoughts are with you."