Vicky Pryce - who was jailed for taking ex-husband Chris Huhne's speeding points - has resumed her role on a panel advising Business Secretary Vince Cable on the economy.
Ms Pryce first joined the panel more than 10 years ago when she was chief economist at the business department.
She was chosen for the unpaid role for her macroeconomic expertise, said a source at the department.
Ex-Lib Dem minister Mr Huhne was also jailed for his part in the deception.
He has quit Parliament and resumed his former career in journalism as a columnist for The Guardian newspaper.
Ms Pryce will join the Monitoring the Economy Panel meets, which meets three times a year.
It is chaired by Lib Dem Mr Cable and has around 25 members including economists from Deutsche Bank, the Office for Budget Responsibility and the Treasury.
A BIS source said: "Vicky Pryce was appointed to the department's monitoring the economy panel over ten years ago when she was chief economist at the DTI.
"As a distinguished economist, she continued to be part of this panel after leaving the department.
"She has now resumed her unpaid position as part of this panel after serving her sentence, which in no way brought into question her ability or judgement as an economist."