'I'm s****ing my pants': Demi Lovato is beside herself as Walking Dead stars Norman Reedus and Andrew Lincoln wish her happy birthday

 According to Daily Mail, her 24th birthday is on Saturday.

But her best present so far came early.

The singer was surprised at a party held for her Friday night by a Snapchat video in which The Walking Dead stars Norman Reedus and Andrew Lincoln sang happy birthday to her. 

Happy surprise! Demi Lovato seemingly wasn't expecting a birthday video sent to her by Norman Reedus and Andrew Lincoln from The Walking Dead on Friday

An excited Demi shared the clip with her fans via her own Snapchat and also tweeted: 'I just got the best birthday video sent from the cast of the walking dead and I'm sh*tting my pants.'

In the clip, Norman and Andrew can be seen standing together as they sing the birthday tune.

Halfway through the song, Norman adds another playful dimension by donning a cartoonish, plastic lion mask.

Demi immediately reacted to the generous gesture by filling her Snapchat caption with six 'surprised' emojis in a row.

Costume party? Halfway through the song, Norman adds another playful dimension by donning a cartoonish, plastic lion mask

'Best birthday video': Demi couldn't contain her excitement at the early and unexpected gift from the two actors

They walk with the dead: Andrew and Norman have a huge fan following in the AMC hit zombie series

Another birthday surprise came in the form of a very unique sort of cake.

While it appeared to be a standard pastry decked out with white frosting, sprinkles and candles, it was in fact made out of a single watermelon.

She documented the cutting of the cake, which revealed the juicy red innards.

Prior to the cake presentation and musical interlude, Demi had been having fun with friends, including Nick Jonas with whom she's on tour, playing laser tag and air hockey. 

Happy birthday Demi!