Hollywood star Bradley Cooper scurried out of a press conference for his film 'Maestro' to talk to a school nurse about his six-year-old daughter Lea.

The 'A Star is Born' actor, who has joint custody of the youngster with his ex-girlfriend Irina Shayk, was 20 minutes into a promotional event for his Netflix film when he said he had to step out.

The 48-year-old actor, who plays composer Leonard Bernstein in the movie, said: "So sorry. The school nurse just called me. Can I just leave the room for a second to call them back and you can keep going. Is that all right?"

According to DailyMail.com, which revealed the call, Cooper said when he returned, "I have to go to the school to do something with Lea that needs… I have to apply something that they won't allow… I have to do it, so it's like a 10 minute walk."

The press conference incident came after nine-time Oscar nominee Cooper pictured with his daughter in New York on 15 December.

Days before, Lea made her red carpet debut alongside her famous dad at a 'Maestro' screening also attended by his co-stars in the movie including Maya Hawke, Matt Bomer, Sarah Silverman and Carey Mulligan.

Lea appears in the film as a younger version of Maya Hawke's character Jamie Bernstein. But after the glitz of the initial photocall with her dad, Lea was seen taking out a coloring book and sitting on the ground of the floor of the Academy Museum of Motion Pictures.