Kanye West and Kim Kardashian West. Picture: Bang Showbiz

Kim Kardashian West was "stressing" about her forthcoming addition to her brood, but is comforted by the fact she heard mothers of four are the "calm of all parents".

The 'Keeping Up with the Kardashians' star and her rapper husband Kanye West will welcome a baby boy into the world in May - their second via surrogacy after daughter Chicago was born in January last year - and although Kim admitted it was harder going from having one child to two, she was feeling anxious about having a "house full" of kids.

However, she is comforted by the fact she's heard that mothers of four are the most "calm" parents.

The 38-year-old reality star - who also has five-year-old daughter North West and son Saint West, three, with Kanye - told Jimmy Fallon on 'The Tonight Show': "I was kind of stressing. 

"My house is so full [but] I heard that parents of four are the most enlightened and calm of all parents."

On the most difficult adjustment to her brood, she added: "I felt the huge change - from one to two.

"That was harder than two to three."

The KKW Beauty businesswoman also revealed that her eldest child North and her son Saint are "finally" playing nice now she is set to become a mother again.

She said: "Saint and North are finally getting along."

Kim previously revealed how North was struggling to take to having a younger brother.

She said: "She needs to still get it together and warm up and be a little bit nicer, but I think she's getting there.

"I saw glimmers of hope a week ago. 

"She's not harmful, she's not hurting him or anything. "She just doesn't want boys in her room."

Kim confirmed her baby news on 'Watch What Happens Live with Andy Cohen' in January. 

An insider recently revealed that the couple had always wanted a "big family" and are blessed to have an "incredible gift" on the way.

A source said previously: "The couple has always wanted a big family and their first time with surrogacy went so well, they decided to do it again. 

"The couple is excited to welcome such an incredible gift in 2019.