The X-Men star will appear in the show's season finale, TV Guide reports.
He will play Cyrus Maxwell, a judge who asks Jane (Brooke Elliot) to take on the case of a death row inmate.
"Drop Dead Diva is thrilled to welcome another stellar actor to the bench. He is a revered actor and we are so lucky to have him," said executive producer Josh Berman.
Davison has also appeared in shows including Harry and the Hendersons, The Practice, Knight Rider, Ghost Whisperer and General Hospital.
Brandy, Quinton Aaron, Patti Stanger, Kathy Griffin, Clay Aiken, Lance Bass, Wanda Sykes, Tony Goldwyn and LeAnn Rimes are among the other stars who have signed up for roles in the new season of Drop Dead Diva.
The show airs on Sundays at 9/8c on Lifetime.