 Most of the remainder of her 2007 high jump season was hampered by an ankle injury.A shoulder injury, which made it difficult for her to throw the javelin, ended her career in heptathlon around this time.For the 2008 indoor season, Hellebaut returned her focus to multi-events and became world champion of pentathlon at the World Indoor Championships in Valencia, where she set a secord for the best high jump result in a women's multi-event competition, clearing 1.99 m.

At the 2008 Summer Olympics, held in Beijing, Hellebaut reached her pinnacle thus far by winning the gold medal in the high jump, ahead of the favorite, Blanka Vlašić of Croatia, with a new outdoor personal best of 2.05 m. Her achievement represented the first-ever athletics gold medal in the Olympics for a Belgian woman, and only the second of any color, one day after Belgium won their first (silver) medal in the 4 × 100 m relay (which later was upgraded to gold after the Russian team was disqualified because of a doping rules infraction by one of their athletes).