Seems like turning 40 is THE thing to do. Here are 40 other people who are doing it this year too!

Cuba Gooding Jr., American actor (January 2)
John Singleton, American film director (January 6)
LL Cool J, American rapper and actor (January 14)
Chad Lowe, American actor (January 15)
Mary Lou Retton, American gymnast (January 24)
Sarah McLachlan, Canadian singer (January 28)
Edward Burns, American actor (January 29)
Lisa Marie Presley, American singer (February 1)
Gary Coleman, American actor (February
Molly Ringwald, American actress (February 18)
Jeri Ryan, American actress (February 22)
Daniel Craig, British actor (March 2)
Mark McGrath, American musician (March 15)
Kenny Chesney, American musician (March 26)
Lucy Lawless, New Zealand actress and singer (March 29)
Céline Dion, Canadian singer (March 30)
Patricia Arquette, American actress (April
Anthony Michael Hall, American actor (April 14)
Ashley Judd, American actress (April 19)
Tony Hawk, American skateboarder (May 12)
Kylie Minogue, Australian singer (May 28)
Jorja Fox, American actress (July 7)
Gillian Anderson, American actress (August 9)
Eric Bana, Australian actor (August 9)
Debra Messing, American actress (August 15)
Rachael Ray, American television chef (August 25)
Will Smith, American rapper and actor (September 25)
James Caviezel, American actor (September 26)
Naomi Watts, English-born actress (September 28)
Jane Krakowski, American actress (October 11)
Hugh Jackman, Australian actor (October 12)
Shaggy, Jamaican singer (October 22)
Vanilla Ice, American rapper (October 31)
Parker Posey, American actress (November
Sammy Sosa, Major League Baseball player (November 12)
Owen Wilson, American actor (November 18)
Jill Hennessy, Canadian actress (November 25)
Lucy Liu, American actress (December 2)
Margaret Cho, Korean-American comedian (December 5)
Rachel Griffiths, Australian actress (December 18)

List compiled by Andi of List-O-Rama