Actor Chad Michael Murray has slammed reports his 18-year-old fiancee is pregnant, insisting the couple are getting married because they are in love.

The One Tree Hill star announced his engagement to Kenzie Dalton, a high school student, last week.

Murray, 24, wed his One Tree Hill co-star Sophia Bush last year and the couple separated last September.

Bush filed for an annulment in February, on grounds of fraud and their divorce has not been finalised.

When asked by US People magazine if the rumors of pregnancy were true Murray says, "Definitely not."

Dalton's mother Jeannie confirms the couple are "crazy for one another."

The pair have not made any final wedding plans, but Murray says he is determined to have a long-lasting relationship this time around.

He adds, "(All I want is) to be 80-years-old and to have been married for 50 years and still be so in love."