(ABC News) - Actor, former underwear model and reality show star Antonio Sabato Jr. — who stumped for Donald Trump on the floor of the Republican National Convention Monday — told ABC News that he "absolutely" believes President Barack Obama is a Muslim.

"We had a Muslim president for 7 1/2 years," Sabato said. "I don't believe he is [a Christian]."

Trump, who spearheaded the birther movement, repeatedly questioned whether the president is an American and if he is a Muslim.

Obama has repeatedly said that he is a Christian.