(CNN) – A rising Republican star considered to be on the party's vice presidential short list will campaign on Monday with likely nominee Mitt Romney, campaign officials told CNN.
Romney and Rubio, a U.S. senator from Florida, will make their first joint campaign appearance outside of Philadelphia, the officials said. Rubio endorsed Romney earlier this month, but the two did not appear together.
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Rubio has thrown water on suggestions he would be picked to join Romney on the GOP ticket, saying as recently as Thursday he would reject such an offer.
"You know that's not going to happen," he said. "The bottom line is I really want to do a good job in the Senate. I think the Senate is a very valid place to shape and drive American policy."
Rubio's Cuban heritage could help Romney close a 40-point disadvantage to President Barack Obama among Hispanic voters, as seen in a recent Pew survey. Rubio's popularity in Florida could also help Romney earn that swing state.
CNN's Jim Acosta, Steve Brusk, Rachel Streitfeld, and Ashley Killough contributed to this report