Michael J. Fox is making his return to the midterm elections.

After cutting some memorable campaign commercials for now-Sens. Ben CardinBen CardinSchumer, Cardin to introduce legislation on Russia sanctions Lawmakers join women's marches in DC and nationwide Senate confirms first nominees of Trump era MORE (D-Md.) and Claire McCaskillClaire McCaskillWashington Post reporter compares DC rioters to Boston Tea Party Dem senator: Violent inauguration protesters ‘disgusting’ Five things to watch for in Mnuchin hearing MORE (D-Mo.) four years ago, Fox is back in a new spot for Sen. Arlen Specter (D-Pa.).

"Arlen Specter is moving forward," Fox says. "He's won the battles to double funding for biomedical research, to find cures and to save lives.

"He's smart, tough and always moving forward."

Fox's 2006 midterm ads for Cardin and McCaskill drew plenty of attention, especially after Rush Limbaugh accused him of exaggerating the effects of his Parkinson's disease during the ads.

Specter faces Rep. Joe Sestak (D-Pa.) in the May 18 primary. If he wins there, polls show he would also face a tough match in November, with former Rep. Pat Toomey (R-Pa.) leading.