James Brolin says his wife Barbra Streisand becomes a different person when she is in the company of children

He said: "The minute a kid comes into the room, she just changes as a person, she falls apart.

"She is persnickety.

"'Who put those flowers there? You moved that, that's supposed to be on the table right there.'

"The minute a kid comes in, all of that just goes out the window and it's just really fabulous to see somebody disarmed."

The 76-year-old Hollywood legend became a grandmother again to her husband's son Josh Brolin's daughter Westlyn - whom he has with wife Kathryn Boyd - five months ago.

James says his 'Avengers: Endgame' actor son, 51, "dropped everything" to look after his third child and spent "three months" on diaper duty.

He told PEOPLE.com: "He dropped everything. You know how busy he was, for sure, he literally stopped everything and nothing but diapering for three months."

Meanwhile, Josh - who also has 30-year-old son Trevor and 25-year-old daughter Eden with ex-spouse Alice Adair - previously admitted Barbra is an "annoying" grandmother - but in a "really great way".

He said: "My wife got her a bracelet that said 'Grandma' on it and she started crying. She is one of those ... it's annoying but in a really great way, [with] emails every day and like, 'Hey, I thought of this name, what do you think of that? ... When can I come over and feel the baby?'"