Its always a little nerve-wracking when you have visitors at work.

But imagine if Barbra Streisand was looking over your shoulder.

Says Cooper, She gave us a blessing.

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Bradley Cooper and Lady Gaga next to Kris Kristofferson and Barbra Streisand in ‘A Star Is Born.'.Neal Preston/Warner Bros.; Everett Collection

Everybody was so excited she was there.

We just looked at each other and were like, Wow.

How are we here right now?

Adds Gaga, She was so, so kind.

Kristofferson also paid a visit one day while the film was shooting at the Chateau Marmont in Los Angeles.

Remembers Gaga, I just burst into tears when I saw him.

But Kristofferson also played a pivotal role in one of the films concert scenes shot at Glastonbury.

That was in front of 80,000 people, says Cooper.

Kris Kristofferson was kind enough to give us four minutes of his set.

I sang, played the guitar solo, and then I said, Ladies and gentlemen, Kris Kristofferson.

The newA Star Is Bornarrives in theaters on Oct. 5.