Camila Alves and Matthew McConaughey

The 'Mud' actor and Camila Alves described their trip to the Veuve Clicquot Polo Classic in New York City this weekend as their first date since the birth of their son, Livingston, five months ago, and he said he couldn't narrow down the sexiest part of her.

He told E! News: "There are all kinds of ways [I find her sexy]. There are ways she is sexy as a woman. There are ways she is sexy as a human. There are ways she is sexy as a mother. There's many angles. I will say that."

Model Camila, 31, looked stunning in a tight yellow Hervé Léger dress and appears to have quickly shed her baby weight, saying she has recently started back with exercising.

She explained: "I just started to exercise two weeks ago. Breastfeeding helps a lot. I am not having dairy. Diet is the main thing for me."

Matthew - who also has children Vida, three, and Levi, who turns five this week, with Camila - has previously said his home life is hectic now he has three children.

He said: "It's wonderful time and I've got a wonderful woman. It's like a circus at home - and she's the ringleader of that circus.

"It's true that with your third child, is not like you've added 33 per cent more, you've added about 133 per cent more."