Benji Madden has thanked his wife Cameron Diaz for inspiring him to be the "best man" he can be as he wished her a happy 46th birthday.

Benji Madden and Cameron Diaz (c) Instagram/Benji Madden

Benji Madden and Cameron Diaz (c) Instagram/Benji Madden

The 39-year-old guitarist took to Instagram to share a sweet tribute to his significant other as she celebrated her latest milestone on Thursday (30.08.18), and he praised her for being "special", admitting he is "so proud" of the 'Other Woman' actress.

He wrote: "Happy Birthday Baby There's so much to write, so many things that make me so proud of you and how special you are Thank you for being the best friend and partner to me and taking this journey of Marriage. The way you live your life everyday, and your compassion for the world shines thru in your eyes and you inspire me to want to be the best man I can be in this lifetime. You're the realest. I'm so grateful to be yours Always&Forever, and to call you my One&Only. True Love (sic)"

Benji captioned his wise words alongside a picture of the couple - who married in 2015 - dressed down in casual clothes while standing next to a lake.

Last year, Cameron admitted she and Benji are "so different from one another", but they are also "both weird enough" to be together.

She said: "I think it's a matter of - I just hadn't met my husband, you know? I had boyfriends before. And there's a really, really distinct difference between husbands and boyfriends. And I have a husband who is ... just my partner in life and in everything. Talk about two very different people, we are so different from one another but we share the same values ... we're totally two peas in a pod. We're both just weird enough for each other."