Actress Hayden Panettiere's future brother-in-law Vitali Klitschko has ended his campaign to become president of his native Ukraine and thrown his support behind a former rival.

The former boxer officially entered the race for office in February (14), following the ousting of leader Viktor Yanukovych, who went into hiding after violent riots erupted on the streets of the nation's capital, Kiev.

However, Klitschko withdrew his name from the upcoming elections on Saturday (29Mar14), choosing instead to back billionaire chocolate maker Petro Poroshenko, who has become a presidential favourite.

The ex-sportsman made the decision to bow out in a bid to avoid splitting votes between him and Poroshenko, so his former rival could focus on defeating ex-Prime Minister Yulia Tymoshenko at the polls.

Klitschko, the older brother of Panettiere's boxer fiance Wladimir, is now planning to enter politics on a local level, by running for the Mayor of Kiev position.

Ukrainians will go to the polls on 25 May (14) to vote for their next leader.