A birthday is a day or anniversary when a person celebrates his or her date of birth. Birthdays are celebrated in numerous cultures, often with a gift, party or rite of passage. Although the major religions celebrate the birth of their founders (e.g., Buddha's Birthday), Christmas – which is celebrated widely by Christians and non-Christians alike – is the most prominent example. In contrast, certain religious groups, as is the case with Jehovah's Witnesses, express opposition to the very idea of celebrating birthdays.

In most legal systems, one becomes a legal adult on a particular birthday (often between 14 and 21), and reaching age-specific milestones confers particular rights and responsibilities. At certain ages, one may become subject to military conscription or become eligible to enlist in the military, to marry without parental consent, to vote, to run for elected office, to legally purchase (or consume) alcohol and tobacco products, to purchase lottery tickets, or to obtain a driver's license.

Katheryn Elizabeth Hudson (born October 25, 1984), known by her stage name Katy Perry, is an American singer, songwriter and actress. Perry grew up with gospel music, and during her first year of high school she pursued a music career as Katy Hudson, releasing her first studio album called Katy Hudson which failed to chart. She recorded a solo album later, which was never released. After signing with Capitol Music Group in 2007, her fourth record label in seven years, she adopted the stage name Katy Perry.

She first gained recognition with the release of her first mainstream album, One of the Boys in 2008, which spawned three Billboard Hot 100 top-ten songs—"I Kissed A Girl", "Hot n Cold" and "Waking Up In Vegas". Perry supported the album with her Hello Katy Tour. In 2010, her third studio album, Teenage Dream (2010), which topped the Billboard 200 chart, and spawned five number one singles—"California Gurls", "Teenage Dream", "Firework", "E.T." and "Last Friday Night (T.G.I.F.)"—Teenage Dream was the only album (after Michael Jackson's Bad)—to do so, and the first female in history to achieve this milestone. She embarked on the California Dreams Tour, which grossed nearly $60 million worldwide. Perry re-released the album under the name of Teenage Dream: The Complete Confection on March 26, 2012, and the re-release has already spawned the number-one single "Part of Me".

Aishwarya Rai, known also as Aishwarya Rai Bachchan after her marriage (Tulu pronunciation [əjɕʋərjaː rəj]; born 1 November 1973) is an Indian film actress. She worked as a model before starting her acting career, and ultimately won the Miss World pageant in 1994. Rai has featured in films in various languages including Hindi, English, Tamil, Telugu, and Bengali.

Often cited by the media as the "most beautiful woman in the world", Rai made her acting debut with Mani Ratnam's Tamil film Iruvar (1997), and had her first commercial success in Jeans (1998). She found success in Bollywood with Sanjay Leela Bhansali's Hum Dil De Chuke Sanam (1999) and Devdas (2002) and eventually won two Filmfare Awards in the Best Actress category.

After a series of unsuccessful films during 2003–2005, she appeared in the blockbuster action thriller Dhoom 2 (2006) and subsequently featured in such films as Guru (2007), Jodhaa Akbar (2008), and Enthiran (2010). She gained critical acclaim for her performances in offbeat, independent films such as Chokher Bali (2003), Raincoat (2004), and Provoked (2007). Rai has thus established herself as one of the leading contemporary actresses of Indian cinema.