The socialite marked the milestone with a whirlwind of parties and TV appearances, but she took time out from her busy schedule to head to the headquarters of the United Service Organizations, which supports soldiers and their families.

Hilton chatted to the military men and posed for photos, even posting a snap on her Twitter.com page.

In the accompanying caption, she writes, ""Went to the USO to meet with the troops. So nice to see them all!""