Sen. Roger Wicker (R-Miss.) will round out Sen. James Inhofe's (R-Okla.) "truth squad" at December's climate change summit in Denmark.
Inhofe, a noted global warming skeptic, will bring along Wicker and Sen. John Barrasso (R-Wyo.), whose attendance had been announced previously.
The trio will join a number of other members of Congress and President Barack Obama at the United Nations' Climate Change Conference in Copenhagen this month.
Inhofe had previously been tight-lipped on the identity of his third travel companion, waiting until this morning to name Wicker as the person.
Inhofe had rejected speculation on a conservative talk radio show last week that former Alaska Gov. Sarah Palin (R) was the third travel companion.