Meghan Trainor is all about that mistletoe.
The singer covered Justin Bieber's Christmas hit during an appearance at 1LIVE radio in Germany -- and Justin Bieber approved. "Nice job @Meghan_Trainor. #Mistletoe :)," Bieber tweeted. The performance follows Bieber covering Trainor's No. 1 Hot 100 hit "All About That Bass" last month.