The Spice Girls singer and the Neighbours veteran both tested their skill at moving an After Eight chocolate mint down their face without using their hands.
The odd stunt was launched last year (14) by retired British soccer star Kenny Dalglish to raise cash for his wife's cancer charity, and participants included Taylor Swift and English comedian Jack Whitehall.
After completing her challenge for this year's (15) campaign, Melanie took to Twitter.com to urge fans to also take part in the fundraiser, writing, "Make sure you get involved with the #AfterEightChallenge this Xmas for the #MarinaDalglishAppeal. Text MINT08 and your donation to 70070."
The Marina Dalglish Appeal raises money to improve cancer care in the U.K.