Pop star Ashlee Simpson has further fuelled speculation she is pregnant by again refusing to be drawn on the claims during the taping for a U.S. TV show.

After Simpson and rocker beau Pete Wentz announced their engagement earlier this month, sources immediately alleged the Boyfriend singer is expecting the couple’s first child.

The pair have since made numerous TV appearances and failed to clear up the rumours - even spoofing them by making a video showing Simpson wearing a fake baby bump.

And the 23-year-old singer remained coy about the subject when she was quizzed about the baby rumors during her appearance on The Ellen DeGeneres Show - which is due to air on Thursday.

When asked directly by host DeGeneres, "Are you or are you not pregnant?" Simpson responded by saying, "Well, that has been going on for quite a while.

That is something that I choose personally not to discuss." DeGeneres then made her promise she would not keep the public guessing for as long as fellow singer Jennifer Lopez - who waited until her swollen belly was so obvious, no one was surprised when she finally confirmed the baby news.

Simpson told DeGeneres: "I swear. I promise you that. I give you my pinky (little finger) on that." The pair then hooked fingers to seal the deal.

She also dodged one final attempt by DeGeneres to catch her out. When asked, "Is it a boy or a girl?" Simpson laughed and responded, "You’re funny."