SPICE Girl Mel C put her oar in during a charity challenge on the Zambezi when she whacked DJ Greg James in the head with a paddle as they tackled some rapids.
BBC Radio 1 star James managed to continue and the group, which includes comic Dara O Briain and actress Chelsee Healey, got off to a good start on their five-day ordeal negotiating the African river.
The group will brave crocodiles and hippos along a stretch of the Zambezi and will be paddling for up to eight hours a day during the BT Red Nose Challenge: Hell and High Water.
O Briain said: "We've done 22 kilometres and I can definitely say the second part of that has been just as painful as the first.
"Chelsee and I have been working as a team. In any usual circumstances, our worlds wouldn't collide, but we've become like an old married couple, bickering about rowing.
"The hardest thing so far is keeping the boat in a straight line. We've spent a surprising amount of today facing the wrong country."
During the 111km journey, they will face rapids known as Gnashing Jaws of Death, the Washing Machine and Oblivion on their way to the world's largest waterfall, Victoria Falls.
The challenge will see them shunning luxury accommodation.
Instead they will be camping on cliff-tops and riverbanks as they nurse their blisters and rest their aching limbs.
Armed guards will accompany them to protect them from wild animals.
The journey, which it is hoped will raise ¤1.16m, is being staged ahead of this year's Red Nose Day which takes place on March 15.