Reese Witherspoon says the most important part of a relationship is finding someone who ''brings out the best'' in her.

The 'Big Little Lies' star has been married to Jim Toth - with whom she has seven-year-old son Tennessee - since 2011, and has said that whilst they do have a shared ''physical attraction'' to one another, the secret to their lasting romance is that they both ''encourage'' each other to ''be the best [they] can be''.

Asked about married life, she said: ''As you get older, you realise that making a relationship isn't just about physical attraction - although that's certainly important. It's about picking the person who brings out the best in you, and encourages you to be the best you can be.''

Reese - who also has Ava, 20, and Deacon, 16, with her ex-spouse Ryan Phillippe - met Jim whilst at a party, when the latter had to step in to save the actress from his friend, who had had too much to drink.

She recalled: ''I met Jim at a party where he was with a friend who had had a lot to drink and was talking to me kind of loud and sort of insistently. Jim said, 'Please excuse my friend, he's had too much to drink but he isn't usually like this - his girlfriend just broke up with him.'

''I just thought it was very sweet of him to be such a good friend to his buddy. I had no idea I'd end up marrying him though!''

The 'Legally Blonde' star, 44, believes she always knew Jim was the right man for her, and nine years into their marriage the couple still have ''the best time'' together.

Speaking to the new issue of Candis magazine, she said: ''We have the best time together. We find humour in everything and have that lovely easy relationship - you know how you get that sort of great feeling when it's all working out.''