Ashlee Simpson and Evan Ross plan to expand their brood next year.

The couple have revealed they are busy working on new music together and separately for their own respective albums, but once their schedules quieten down, they plan on trying for another child.

Asked about the prospect of giving their three-year-old daughter Jagger a sibling, Ashlee - who also has nine-year-old son Bronx from her former marriage to Fall Out Boy rocker Pete Wentz - said: ''It's definitely soon... in the next year. Definitely in the next year would be nice.''

Fans will be in for a treat, as the couple are going to be dropping a new song on every episode of their forthcoming E! series 'ASHLEE+EVAN', which airs on September 4.

The 'Pieces of Me' hitmaker revealed to E!: ''We'll be releasing a song per episode--or somewhat per episode--so people will be able to kind of live in our experience.''

Ashlee is currently putting together her first record since 2008's 'Bittersweet World'.

Whilst Evan - who is the son of music legend Diana Ross - is working on an album too, and the pair are even planning on hitting the road together.

Speaking about the projects he has in the pipeline, including one with 'Empire' director Lee Daniels, he said: ''I obviously want to work on my album, as well as, Ashlee wants to work on hers and still tour together.

''I'm excited to start working on this new project that I'm doing with Lee Daniels. There's a lot of big, new things that I'm excited about.''