Lucy, who hosts the X Ray current affairs programme with her husband, Rhodri, pulled a muscle in her back during the final stages of preparations for the Strictly Come Dancing style competition.
With hours to go before her TV spot Lucy called on the Wales Team Physiotherapist Mark Davies to help her recover in time for the Friday night show.
Mark instantly agreed to treat her injury and eased her pain enough to face the cameras at the Millennium Centre in a competition against rival BBC Wales presenter teams in the charity special.
Lucy turned up at the Millennium Stadium and waited for the full Wales squad to finish their final run out before the Saturday international against Argentina.
When the team had left the changing room to return to their Vale Resort Hotel base Mark stayed on to assess Lucy's problem and help with treatment and advice.
Lucy said:"Mark was absolutely great and I want to thank him and the Welsh Rugby Union for helping me in my hour of need.
"I was a bit taken aback when Mark warned me I might have to "dig in" and accept some pain when I danced but my injury was a lot easier after he located the trouble spot and treated the cause of the problem.
"I asked him if he was used to dealing with bigger injuries when he treated the players and I must say he did smile at that.
"I have always been a Wales rugby fan but I will cheer them on that extra bit louder in future for the way I was helped out."
Some tickets from a starting price of £25 are still available for the match between Wales and Argentina which kicks off at the Millennium Stadium at 2.30pm on Saturday.
Tickets are on sale from all the usual outlets including the Cardiff Arms store and visitor centre in Westgate Street near ground entrance 3. which opens at 9am on matchday