Nicole Scherzinger is ''hoping'' for a reunion with her ex-boyfriend.

The 'Poison' hitmaker is reportedly desperate for Formula One racing driver Lewis Hamilton to come ''running back'' to her and she let her emotions get the better of her as she celebrated her birthday with pals.

A source told Closer magazine: ''Nicole was determined to go wild for her birthday and spent most of the day drinking cocktails and champagne, even though her pals warned her to slow down.

''But she received a birthday message from Lewis at the end of the night, as well as an Instagram post, which made her feel incredibly emotional. Deep down she still loves him and had been hoping that he'd come running back and finally commit.''

In the sweet birthday tribute, the 30-year-old sports star said Nicole, 37, ''made him the man'' he is now.

He wrote: Dear friend, Through the years we shared alot, i wouldn't have changed a thing. All the experiences made me the man i'm proud to be right now.

''The Memories together will never be taken away no matter how old we get and I'm thankful for the time we had. I'm wishing you the Happiest of Birthdays, and may God continue to Bless you in all that you do. #waayyyupstayblessed (sic).''