Nicole Kidman was given a special musical treat at her husband Keith Urban's gig in Illinois on Saturday night - when 50,000 fans joined the country star to wish her a happy 41st birthday.

Urban was playing at Chicago's Soldier Field when he dedicated his song Who Wouldn't Wanna Be Me to the pregnant actress, who turned 41 on Friday.

He then brought her out on stage and invited the arena's audience to help him make Kidman's birthday extra special.

He told the crowd, "It would be nice to have 50,000 people sing 'Happy Birthday' to her."

After the birthday rendition, Kidman blew a kiss to the crowd and returned backstage to watch the rest of Urban's concert from the side of the stage, reports People.com.

The couple is expecting their first child together this summer.

- Nicole Kidman Pictures
- Keith Urban Photos

(This news article provided by World Entertainment News Network)