If Bill Clinton's presidency was a "two for the price of one" -- thanks to Hillary Clinton's presence as first lady -- Bernie Sanders says his presidency would be a "two-fer."

Sanders noted on Monday's "Late Show with Stephen Colbert" that Fox News host Bill O'Reilly has promised to move to Ireland if Sanders is elected.

"Electing me for president is a two-fer; you get Sanders, and you get Bill to go to Ireland," Sanders joked.

Later on, when asked again about something said by O'Reilly, who was on Colbert's show earlier this week, Sanders quipped: "Not to disagree with my good friend Bill O'Reilly, but he's -- as usual -- wrong."

Sanders also lent Colbert a hand in opening the show, even dropping a few one-liners.