Michelle Williams ''fell in love'' with her best friend Busy Philipps when they first met on the set of 'Dawson's Creek'.

The 37-year-old actress - who has 12-year-old daughter Matilda with her late former partner Heath Ledger - first met Busy when the 'Cougar Town' star joined the cast of 'Dawson's Creek' in 2001, and has revealed the pair experienced a love at first sight connection and immediately hit it off.

Michelle explained: ''Someone had said, 'when you two meet, there is going to be a chemical reaction.' I had been really excited for this girl to land in Wilmington [North Carolina].

''She was so beautiful and cool. She wore overalls and her hair was in braids and she was so real, tough and funny. We became inseparable and I fell in love with her.''

And it isn't just their shared stardom that makes them the best of friends either, as Busy - who has Birdie, nine, and Cricket, four, with her husband Marc Silverstein - insists the pair share a love for many other hobbies too.

The 38-year-old star said: ''We both had our kids around the same time. We are interested in the same kinds of books and poetry and music, wine and beach vacations.''

Michelle even admits she isn't sure ''what or who'' she would be if she had never met her pal.

Speaking to People magazine, she said: ''I said to her recently, 'you have really saved me from every being lonely because you are always right there'. We are so close and can tell each other everything. I don't know what I would be or who would be without Busy.''

Most notably, Busy was there for Michelle when her former partner Heath took his own life in 2008, and recently recalled feeling ''protective'' of her friend and her daughter - who was two at the time of Heath's passing - in the wake of the tragedy.

Busy said: ''That anniversary, just brought up a lot of ... I can't believe it's been 10 years. I was pregnant with Birdie. I had seen him a couple months earlier, and you know, [Williams and Ledger] were broken up. I've never talked about it. I've never shared it, because I'm hyper protective of [Williams] and her daughter. But I also think ... I think it's OK. Everyone's allowed to have their own feelings about something that happens.''