Cast member Jennifer Aniston arrives for the premiere of the film "We're the Millers" in New York, August 1, 2013. (REUTERS/Keith Bedford)

Rumours that Hollywood A-lister Jennifer Aniston is pregnant were reignited when the former Friends actress appeared at the premiere of We're the Millers in New York City.

The 44-year-old star showed off her toned figure in a strapless Burberry dress - but a little round bump in her stomach led to fresh speculation that a baby is on the way.

Recept reports suggest Aniston, who has no children, has undergone IVF treatment in a bid to get pregnant, despite denials from her representative Stephen Huvane.

Aniston, who is engaged to fellow actor Justin Theroux, has stayed silent on reports of her pregnancy. However, that has not stopped the rumour mill from turning at a furious rate.

"She definitely seemed to have gained some weight," an eyewitness from the set of Jennifer's latest movie Squirrels to the Nuts told In Touch magazine.

"According to new reports, Jen has begun IVF treatments, and if all goes as planned, she will be pregnant by her 45th birthday on February 11. She held her script right in front of her stomach."

For the We're the Millers premiere, Aniston teamed her satin dress with a pair of grape colour strappy suede heels and matching colour of the nail paint. She left her tresses lose, reaching perfectly below her shoulders.

Here's how Jennifer Aniston looked at We're the Millers premiere in New York.

Jennifer wore plum dress to the premiere
Jennifer wore plum dress to the premiere (Photo: Reuters)
The actress is engaged to Justin Theroux. (Photo: Reuters)
The actress is engaged to Justin Theroux. (Photo: Reuters)
A little bump has sparked Aniston's pregnancy rumors. (Photo: Reuters)
A little bump has sparked Aniston's pregnancy rumors. (Photo: Reuters)
(L - R) Cast members Will Poulter, Emma Roberts, Jennifer Aniston, Jason Sudeikis and director Rawson Marshall Thurber arrive for the premiere of the film "We're the Millers" in New York, August 1, 2013. (Photo: REUTERS/Keith Bedford)
(L - R) Cast members Will Poulter, Emma Roberts, Jennifer Aniston, Jason Sudeikis and director Rawson Marshall Thurber arrive for the premiere of the film "We're the Millers" in New York, August 1, 2013. (Photo: REUTERS/Keith Bedford)