Becoming a mother is Christina Aguilera's greatest achievement.

The singer gave birth to her son Max Liron - which means 'greatest song' - in January 2008 and rates having him with former husband Jordan Bratman above anything else she has ever done in her life.

She said: ''The birth of my son is my proudest moment. Max is my greatest song.''

'The Voice' mentor is taking time off from the show next year to focus on her music career and admitted she will miss her fellow coaches - Cee Lo Green, Adam Levine and Blake Shelton - and the contestants.

She added in an interview with America's OK! magazine: ''The coaches are like big brothers and the contestants are so hungry. I am better for it but I need to take a break to do my own thing, to bring so much back to them.''

Christina, 31, recently revealed she is embracing the aging process and has no fear of getting older.

She said: ''Some people are afraid of change and [feel] that getting older is a bad thing, but I really love maturing and gaining wisdom.

''And the experience of being pregnant and having a child and seeing what a woman's body can do is amazing.''