Rachel Mcadams is planning to return to the lake where she shot scenes for new romantic drama The Vow in Toronto this summer (12) - because she's convinced it's one of the cleanest water spots in North America.

The actress stripped down to her underwear for swimming scenes and was pleasantly surprised to find the water warm and clean.

And now McAdams can't wait to go back.

She tells WENN, "I thought I was going to get pink eye and it would be so cold and I'll cut myself on shards of glass in the water. I just thought it would be a nightmare. It turns out the water was so lovely; it was like bath water.

"They even tested the water and it was so clean. They cleaned it out the best they could because they didn't want us to fall and there'd be a shard of glass or something, so they laid down carpet. I don't remember the last time you could swim in Toronto waters... I'm very excited about for next summer!"