Ryan Reynolds has joked that Betty White is his ''ex-girlfriend'' in a birthday tribute to the iconic actress.

The 'Deadpool' star - who is married to Blake Lively - took to social media on Thursday (17.01.19) to wish the 'Golden Girls' actress a happy birthday as she turned 97 years old, and joked that he had once been in a relationship with the television star, who is more than 50 years her junior.

Posting a picture on Instagram of himself and Betty during an appearance on a late night talk show, the 42-year-old actor wrote: ''I don't usually wish ex-girlfriends Happy Birthday. But Betty's special. Happy Birthday to the one and only, @bettymwhite (sic)''

Betty's impressive birthday milestone comes just a few months after she received a standing ovation at the Primetime Emmy Awards, where she spoke about being dubbed as the ''First Lady of television''.

She said at the time: ''Somebody said something the other day about first lady of television, and I took it as a big compliment.

''And then I heard her talking to her daughter a little later, and she said, 'First lady, she's that old. She was the first one way back.'''

But the 'Hot in Cleveland' star admitted it is ''incredible'' her career had lasted so long.

She said: ''Little did I dream then, that I would be here and it's incredible that I'm still in this business and that you are still putting up with me,'' White said. ''I am thanking you. It's incredible that you can stay in a career this long and still have people put up with you. I wish they did that at home.''