Josh Duhamel sent Fergie flowers following her critically-panned rendition of the US national anthem at the NBA All-Star game last month.

The 45-year-old actor reached out to his estranged wife - who he split from last year - to try and cheer her up after she was widely criticised for her slowed down take on the 'Star-Spangled Banner' because he wanted her to know he was ''on [her] side''.

He said of the bouquet: !I didn't know what else to do. I was like, 'I just want you to know, I got your back, girl. I'm with you, I'm on your side.'

''The girl's amazingly talented, she really truly is. And by the way, her album is amazing. She's had a challenging year but she is resilient.''

The 'Transformers' actor admitted he was ''surprised'' when he caught Fergie's performance at the high-profile basketball game because he's heard her sing the anthem better and he ''felt bad'' for the 'Save It Til Morning' singer because of the cruel comments she received.

Speaking on 'The Dan Patrick Show', he said: ''I was on my way back from the airport when I heard.

''So, I saw it when I got home. I felt, I mean I've seen the girl sing it several times -- Daytona 500, Patriots, Dolphins home opener -- and she crushes the song, so I was surprised to see she tried what she did.

''But more than that, I just felt bad for her. There's an army of trolls out there who are just ready to pounce and they were not nice. And for that, I feel bad but she's a really tough girl.''

Josh - who has four-year-old son Axl with Fergie - instinctively wanted to speak up and defend the 42-year-old singer but it felt it was best to take a step back.

He said: ''It's not easy. Someone you care about getting hammered like that is not easy.

''And I wanted to defend her, too. I wanted to pull the tapes out from Daytona 500, like, 'Look at this! She's really good at singing this song!'

''But I was like, 'I gotta just stay out of this. It's that protective thing in you, but she's doing great.''

The Black Eyed Peas singer previously issued an apology for her controversial performance, stating she ''tried her best'' to do something different, but that it just didn't work out in her favour.

She said in a statement: ''I've always been honoured and proud to perform the national anthem and last night I wanted to try something special for the NBA. I'm a risk taker artistically, but clearly this rendition didn't strike the intended tone. I love this country and honestly tried my best.''

Fergie's performance was slammed by viewers as ''the worst ever'', and several celebrities also took to social media to express their confusion at the divisive rendition.

Roseanne Barr - who performed a crotch-grabbing rendition of the tune in 1990 - wrote on Twitter: ''Who saw Fergie's national anthem performance at the NBA All Star Game? I think mine was better lowkey (sic)''