Christina Aguilera and Lady Gaga ended the year with a powerful duet. Stories have been rampant that the two women with the big voices have been in celebrity feud all year, but Christina and Gaga didn't let that get in the way of their performance last night.

Aguilera took on the role of R. Kelly in Lady Gaga's hit "Do What You Want," but they didn't get it on like Lady Gaga and Kelly have been doing in their TV pair-ups. It was all about "The Voice."

Christina Aguilera and Lady Gaga performed together for the first time on the season closer of "The Voice."  There have been rumors of a rivalry and strong animosity between the two singers, but not at "The Voice" performance in Universal City, Calif.

The feud between the two singers was started by Christina Aguilera in 2008 when Lady Gaga was just starting to make waves across the charts. It's all over now.

Wearing matching lamé outfits the only feud last night was the competition of who had the bigger voice, Lady Gaga and Christina Aguilera both have an incredible range. They even toasted each other with champagne.

Lady Gaga can't say no to anything,  not even a Muppets Thanksgiving Christmas. Lady Gaga said "I was really excited because The Voice called and wanted me to perform on the finale and I obviously can't refuse. It's such an amazing show and I said, 'I'll do it, but I want to know if Christina will do it with me."

Christina Aguilera was on board in an instant. She said "This is the first time we've ever met and I have to say, when I heard she wanted to collaborate I said, 'Of course! Lady Gaga!' I've been waiting to meet her. She's such an innovative artist and a risk taker and as a fellow female, I have so much respect for that. She's the most down to earth real person that I've ever met in this business. Female to female in this industry, it's really hard to find that kind of a person. I love you girl, and you deserve everything that you've earned."

After "The Voice" performance was broadcast, Christina Aguilera took to Twitter to gush about Lady Gaga, "She is such a powerhouse vocalist and I was honored to join the stage with @ladygaga tonight on #TheVoice!"

On the Sept. 11 episode of Bravo's Watch What Happens Live, Lady Gaga said "I'm a very big fan of Christina Aguilera. From the very beginning of when my career started, there was all this controversy about the two of us. I always felt that it was very unfair. All I know is that people were talking about Christina Aguilera and Lady Gaga in the same sentence, and I was nobody! I just think it's very unfair of anyone to pit another woman against another woman, especially in the space of music when we are all just trying to be taken seriously. Christina is an incredible vocalist and an incredible artist. From me to her, I'm so sorry for anything that anyone ever said to her because of my existence. And I hope that she never felt any way about it, because when I was 15, I was singing 'I Turn to You' at the top of my lungs trying to hit all her notes. So she was an inspiration to me to have a wider vocal range, and I just think it's all total nonsense the way that they do that."