Senior Judge Robert "Bert" Richardson's appointment will review a complaint filed by Texans for Public Justice, an Austin watchdog group, accusing Perry of bribery and coercion. The special prosecutor will determine whether the facts warrant court action or dismissal.
The group's complaint accuses Perry of bribery, coercion and official oppression.
Perry spokesman Josh Havens said the governor simply was exercising his constitutional veto authority.
"It is not Rick Perry's job to try to remove me from office," Lehmberg said. "His attempts to do that - to coerce me through a veto - I think could be illegal. I didn't appreciate it in the least, and I didn't respond."
Lehmberg, who served 22 days in jail after her April guilty plea, faces a Travis County lawsuit seeking her removal from office.
The Texans for Public Justice complaint, filed in June, contends that Perry threatened to veto funding for the Travis County district attorney's Public Integrity Unit unless Lehmberg resigned. The governor ended up vetoing $3.7 million in annual state funding for the Public Integrity Unit.
