Jennifer Aniston and Justin Theroux are said to be expecting their first child together, according to numerous reports this afternoon.

The Friends star, who has been surrounded by pregnancy rumours since the start of the year, is said to have delayed an announcement because she wanted to get the first few months over with safely.

A source told Us Weekly: “She is scared of having a miscarriage, given her age, so they are not saying anything until she is six months along.”

The insider added that the couple are over the moon: “They’re extremely happy. This is the baby Jen always wanted.”

If it is true it certainly explains why Jen and Justin, who got engaged last August, have been putting their wedding plans on hold.

The couple sparked pregnancy rumours on the red carpet earlier this year.

UPDATE (10.46am): Jennifer Aniston’s rep has denied reports that the actress is pregnant with her first child.

Following the report by Us Weekly, the spokesperson told the Daily News: “The entire story is a fabrication. Jennifer is not pregnant.”