Kanye West is ''crazy'' about his children.

The 'Famous' rapper - who has daughter North, four, and son Saint, 18 months, with wife Kim Kardashian West - believes it is ''crucial'' to have his family around him and credits his kids for keeping him grounded.

A source told the New York Post newspaper's Page Six column: ''He loves being a part of the [Kardashian] family and to involve them in the upbringing of his kids.

''People forget that he has a big family . . . so family has always been crucial. And he wants his kids to have that. He's crazy about his kids. They keep him grounded.''

Kanye, 40, and his 36-year-old wife have reportedly hired a surrogate to carry their third child because the 'Keeping Up With the Kardashians' star has been warned getting pregnant again would be very dangerous, and the 'Only One' hitmaker can't wait to expand their family.

The source added of the planned addition: ''Kanye is extremely excited.''

It was revealed earlier this week the couple have made an agreement with a surrogate via an agency.

It is believed the couple are willing to pay the unnamed woman $45,000 in 10 equal instalments, though if it is a multiple pregnancy she will receive an additional $5,000 per child.

In addition, if the surrogate loses reproductive organs in the process, she receives an additional $4,000.

They are also required to deposit $68,850 with the agency.

In return, the surrogate must refrain from smoking, drinking and drugs during the pregnancy, and she cannot go in hot tubs or saunas, handle or change cat litter, apply hair dye, drink more than one caffeinated drink per day or eat raw fish.

She has also agreed to restrict sexual activity in the weeks leading up to getting pregnant including foregoing intercourse for three weeks after embryo implantation.

The agreement also states the famous couple ''assume the legal and parental responsibilities for any child ... that may possess any congenital or other abnormalities or defects.''