0217_aguilera_launch
Christina Aguilera
can add another engagement ring to her jewelry collection!

"The Voice" coach -- who got engaged on Valentine's Day to longtime love Matt Rutler -- showed off her new ring via Twitter on Friday. 

"He asked and I said ..." she posted, along with a photo of the two holding hands -- with her huge rock on display.  

The singer and her now-fiance first met on the set of "Burlesque" back in 2010 ... while Xtina was still going through a divorce with ex-hubby Jordan Bratman (below). 

0217_aguilera_split
Both of the rings are giant -- Rutler's engagement bling has a much more vintage feel to it, while her ring from Bratman definitely had a more modern look. 

Which engagement ring do you prefer? Cast your vote below, and check out even more celebrity wedding and engagement bling in the gallery above!