Scarlett Johansson and Ryan Reynolds' relationship is reportedly on the rocks.

The 23-year-old star - who has been dating the 'Definitely, Maybe' actor for a year - feels she is too young to settle down and wants to concentrate on her career.

A source said: "Scarlett and Ryan have hit a rough patch after he dared to broach the subject of marriage and kids. Scarlett is younger and has no desire for a husband or family just yet."

It was recently reported Scarlett had moved into Ryan's Los Angeles home even though her mother didn't approve. However, friends say she is just using his home as a base while she travels the world working on movies.

One said: "Scarlett hasn't moved in full-time. She has just moved in so when she stays over she has some belongings there. She is very much focused on her career and is filming three movies back-to-back this year."