Chris Rock could be set to lose custody of his children.

The 49-year-old comedian filed for divorce from his wife Malaak Compton-Rock last week after 19 years of marriage and she's now said to be planning to prevent him from seeing his daughters, while he wants shared legal and physical custody.

A source revealed: ''He lives for his children. They come first. When he was doing a publicity tour for 'Top Five', he made it clear it had to be scheduled around being able to take his daughters to school and pick them up.''

Chris and Malaak, 45, are said to have signed a pre-nuptial agreement in 1996 but it's been claimed the legal document could be a ''key battleground'' in their upcoming divorce case as Chris reportedly argues it's now void after so many years of marriage.

Meanwhile, although the couple have only recently announced their separation, problems are said to have been present in the marriage for ''some time''.

The source told the New York Post newspaper's PageSix: ''Chris just wasn't happy in the marriage anymore. There is no third party involved ... Chris and his wife had previously separated and got back together, so there have been problems for some time.''