Another Simpson wedding?

Jessica Simpson is reported to be engaged to her boyfriend, Dallas Cowboys star Tony Romo.

A source is said to have told America's Star magazine that Simpson, 27, is desperate to make her way down the aisle before her younger sister, Ashlee, who is engaged to Fall Out Boy bassist Pete Wentz.

The rumours were further triggered when Simpson's friends were overheard toasting her happiness at a party for rapper P Diddy in Hollywood.

"Jessica would love nothing more than to get married before Ashlee. It upsets [Jessica] that her little sister will be married and she won't. She gets jealous when Ash gets more attention," said the unnamed source, according to the Star.

Jessica was previously married to Nick Lachey, with whom she starred in reality television series Newlyweds. They announced their divorce in 2005 after three years of marriage.

Earlier this month, she credited Romo with turning her life around, telling US Glamour: "He made me feel comfortable [being myself] again".

Ashlee Simpson announced her engagement last month, although rumours that she is also pregnant were quickly quashed by Wentz himself.

She was pictured over the weekend loking relaxed in casual attire after an appearance to promote her new single on Radio 1.