Jennifer Lopez and Marc Anthony are reportedly expecting twins, the first offspring for the pair.

Speculations about Jennifer Lopez’s pregnancy have been whirling for a while now but the diva has so far refused to confirm or deny the rumors.

Celebrity gossip site TMZ.com is nevertheless mighty confident that the diva is pregnant, which would explain a visible baby bump she has been trying to hide over the past couple of weeks under very flowing outfits.

Currently on a joint tour with husband and fellow musician Marc Anthony, Jennifer surprised fans by appearing on stage with fuller than usual dresses, covering her up pretty well.

One particular show earlier this week generated quite a buzz, when her flowing Roberto Cavalli halter top swirled above her midriff, revealing a visible bump.

If indeed pregnant, the baby (or babies) would be the first for Jennifer, 39. Husband Marc has a daughter and two sons from two previous relationships.

U.S. magazine In Touch reported in mid-September that the singing couple learned they were parents-to-be when they visited Jennifer’s Beverly Hills gynecologist, fertility specialist Dr Robert Katz. She is reportedly due in spring.

As to the possibility of having twins, the magazine quoted a source saying: “The way the fetus is lying made it difficult for the doctor to tell if there was more than one baby in there.”

Married in June 2004, Jennifer and Marc have been partners in more ways than one. They recorded the duets “No Me Ames,” on Jennifer’s 1999 album “On the 6” and “Escapémonos” on Marc’s 2004 album “Amar Sin Mentiras,” among others.

They also starred in “El Cantante,” a biopic about salsa legend Hector Lavoe, released in early August this year. Marc stars as the title character, while Jennifer plays Lavoe’s wife, Nilda.

The musical couple’s joint tour, called “En Concierto,” debuted in New Jersey on Sept. 29. and ends Nov. 4, in Florida.

Jennifer's new album “Brave” hits stores next Tuesday Oct. 9.