These celebrities seem to have clocked up a lot of experience in a short space of time, but is all that it seems?

This lot are actually part of the exclusive group of leap year babies who end up with two different ages. One is a true age based on the number of full years they’ve been on this planet, while the other is their younger age celebrating the actual proper birthdays they’ve been able to celebrate on February 29.

1. Chris Conley

Chris Conley performs
(Mary/Flickr)

The American musician famous as the frontman of Saves The Day was born in 1980, making him eight-and-three-quarters, or 34 years old.

2. Ja Rule

Ja Rule
(Eduardo Santos/Flickr)

For a nine-year-old, Ja Rule’s accomplished a lot. The rapper has starred in 20 films, won several awards for his music and has three children, but then again, he’s also 38.

3. Antonio Sabato Jr

This Italian-born actor became famous for modelling Calvin Klein underwear and for his role on soap opera General Hospital. This year, he’ll be turning 43, but is really only ten-and-three-quarters.

4. Saul Stacey Williams

Saul Williams performs at Lollapalooza
(Russel A. Daniels/AP)

Famed for blending poetry and hip-hop, this 10-year-old (really 42) hasn’t done too badly. He took the lead role in the film Slam in 1998 and Holler If Ya Hear Me on Broadway.

5. Wendi Peters

Wendi Peters arrives at the premiere of Disney's High School Musical
(Matt Crossick/PA)

The Coronation Street actress was born in 1968, making her a meagre 11 years old. Not bad for someone who’s appeared on Celebrity Masterchef, Celebrity Mastermind and Countdown.

6. Darren Ambrose

Darren Ambrose, Ipswich Town
(Chris Ison/PA)

The Ipswitch Town attacking midfielder was born in 1984, making him just seven-and-three-quarters this year.

7. Tony Robbins

Tony Robbins talks during an interview
(Jeff Christensen/AP)

Making Forbes magazine’s Celebrity 100 list is no mean feat for a 13-year-old, but since Tony’s birth in 1960 (he’s 54 if you do the quick maths) he has also co-hosted with Oprah and published three self-help books.

8. Jono Coleman

Jono Coleman arrives at the Arqiva Commercial Radio Awards
(Ian West/PA)

This Ango-Australian TV personality shot to fame as a radio presenter on Virgin and Heart 106.2, all before his 15th birthday, but he’s actually 68 so that’s OK.

9. Alex Rocco

Actor Alex Rocco holds up his Emmy award during his acceptance speech at the 42nd Annual Primetime Emmy Awards
(NICK UT/AP)

The Godfather star has appeared in dozens of films, and although he may be in his 79th year, he’s really just 19-and-three-quarters.

10. Jessica Long

Paralympic Swimmer Jessica Long poses for a portrait during 2012 USOC Media Summit at Hilton Anatole Resort
(Mohammad Khursheed/LANDOV)

She hasn’t yet officially celebrated her sixth birthday, but Jessica Long, born in 1992, holds the world record in 10 paralympic events. The Russian-born US swimmer also has 12 Olympic gold medals.