They also share a corny "believe in yourself and you can achieve anything" message. Structually they're similar, with deliberately paced English verses, building up in speed until the African chorus (don't know what languages they are).
I'll admit that "sounds almost exactly the same" is perhaps overstating it a little. Before listening to them both, I was sceptical of the link and thought people were just looking at the Waka/Haba similarity. The lyrics "Waka Waka" and "Haba Haba" are used differently in the chorus, but they still sound melodically similar to me.